Patent Description:
The present disclosure relates to a display device with improved brightness and display power efficiency. The improved backlight includes a polarization device configured to increase polarization of the light incident on a light guide. The increased polarization provides improved power efficiency and brightness.

Displays, especially three-dimensional (3D) holographic displays, suffer from problems of low brightness and low power efficiency. Publication <CIT> discloses a surface illumination apparatus. The surface illumination apparatus comprises a light source, an end-surface light-guide portion which guides light emitted from the light source in a long-side direction thereof and generates emitted light in a short-side direction thereof, and a light guide plate which allows the emitted light to be incident upon an end-surface portion thereof and emits the incident light from one main-surface portion thereof. The end-surface light-guide portion includes a plurality of polarization control portions arranged in the long-side direction. Each polarization control portion has a half-wave plate and a polarizing prism. The end-surface light-guide portion emits the emitted light in the form of either of S-polarized light and P-polarized light, using the plurality of polarization control portions. The light guide plate emits, as output light, either of S-polarized light and P-polarized light from the one main-surface portion.

Publication <CIT> discloses an optical system. The optical system comprises a substrate and a light source. The s-polarized input light-waves from the light source are coupled into a light-guide through its entrance surface. Following reflection-off of a polarizing beamsplitter, the light-waves are coupled-out of the substrate through an external surface of the light-guide. The light-waves then pass through a quarter-wavelength retardation plate, reflected by a reflecting optical element, e.g., a flat mirror, return to pass again through the retardation plate, and re-enter the light-guide through external surface. The now p-polarized light-waves pass through the polarizing beamsplitter and are coupled out of the light-guide through an external surface of the light-guide. The light-waves then pass through a second quarter-wavelength retardation plate, collimated by a component, e.g., a lens, at its reflecting surface, return to pass again through the retardation plate, and re-enter the light-guide through the external surface. The now s-polarized light-waves reflect-off the polarizing beamsplitter and exit the light-guide through the exit surface.

Publication <CIT> discloses an illumination device comprising a light source including multiple light emitting modules, an array of taper light pipes, a polarization converter, and a taper light pipe. The polarization converter comprises a first polarization beam splitter and a second polarization beam splitter arranged parallel with each other. The first polarization beam splitter is arranged with an angle, for example, <NUM> degree, with the array of taper light pipes. When the light comes out from the second end of the taper light pipes, a first polarization type (for example, P-type) light transmits through the first polarization beam splitter, while the second polarization type (for example, S-type) light is reflected and incident onto the second polarization beam splitter. Being further reflected by the second polarization beam splitter, the second polarization type light transmits through a half-wave plate to be converted into a first polarization type light. The taper light pipe is disposed in front of the polarization converter to receive the first polarization type light coming out from the polarization converter.

Publication <CIT> discloses a head-up display apparatus including an image display apparatus generating image light to be projected, an optical system performing predetermined correction to the image light emitted from the image display apparatus, and a concave mirror reflecting the image light corrected by the optical system to project it onto a windshield or combiner. The image display apparatus includes a solid light source, a collimating optical system converting, into parallel light, the light from the solid light source, a lighting optical system configured by an optical member that polarizes a direction of a light beam generated by the collimating optical system and simultaneously expands a width of the light beam, and a display apparatus. Embodiments herein provide improved brightness and power efficiency.

The figures show various views of an apparatus, including a lens that can shape light emerging from one or more light emitting diodes (LEDs), in accordance with some embodiments. In the views presented herein, it is assumed that light emerges from a front of the lens, such that the LED or LEDs can be positioned towards a rear of the lens. The terms "front," "rear," "top," "bottom, "side," are to be understood relative to one another with "front" and "rear" opposing each other, top and bottom opposing each other, and side between the top and bottom. Other directional terms are used merely for convenience in describing the lens and other elements and should not be construed as limiting in any way.

Corresponding reference characters indicate corresponding parts throughout the several views. Elements in the drawings are not necessarily drawn to scale. The configurations shown in the drawings are merely examples and should not be construed as limiting the scope of the disclosed subject matter in any manner.

<FIG> illustrates, by way of example, a diagram of an embodiment of a backlight unit <NUM>, not forming part of the claimed invention, comprising a planar light guide <NUM> disposed over a protection plate <NUM>, and a light emitting element <NUM> disposed on a side of the light guide <NUM>. Some light <NUM> entering the light guide <NUM> from the light emitting element <NUM> is reflected towards a top surface <NUM> of the light guide <NUM> by a patterned bottom surface <NUM> and another optional reflection sheet positioned between the light guide <NUM> and backplate <NUM> and exits from the light guide <NUM>. Light <NUM> that exits provides backlight to a display <NUM> (e.g., a liquid crystal display (LCD)) on an opposite side of the light guide <NUM> as the reflection sheet <NUM>. The reflection sheet <NUM> is separated from the bottom surface <NUM> by a an air gap <NUM>. The reflection sheet <NUM> can include a polarization maintaining surface, such as a mirror. The reflection sheet <NUM> can include a scattering surface (e.g., a white painted surface). The pattern can be printed or molded on the surface <NUM>, for example.

<FIG> illustrates, by way of example, a diagram of an embodiment of a backlight unit <NUM>, not forming part of the claimed invention, comprising a planar light guide <NUM> disposed over a protection plate <NUM>. The planar light guide <NUM> is similar to the light guide <NUM> of <FIG> with a patterned top surface <NUM> instead of a patterned bottom surface <NUM>.

In some embodiments, the light emitting element <NUM> can be a rectangular single line array or multiple line array. In other embodiments, the light emitting element <NUM> can be formed or otherwise fabricated in a shape approximating a nonrectangular (e.g., circular or oval) shape. Light emitting elements, such as light emitting diodes (LEDs) can be of a single or multiple colors, or in some embodiments red, green, blue (RGB) arrays. Different color pixels can be interleaved, or in other embodiments, the different color pixels can have other groupings in which groups of one color are disposed together in one or both orthogonal directions. In other embodiments at least some of the sets of light emitting elements can provide different wavelengths of light for color tuning. For example, one set of light emitting elements can provide white light while the other set of light emitting elements may provide red light. The light emitting elements can be formed from a II-VI, III-V, or other compound semiconductor that may be a binary, ternary, quaternary, or other compound. For example, gallium nitride (GaN) is used for blue LEDs, gallium arsenide (GaAs) for infrared (IR) LEDs, and indium gallium phosphide (InGaP), indium gallium aluminum phosphide (InGaAlP), or indium gallium arsenic phosphide (InGaAsP) for visible LEDs, among others. Alternatively, a wavelength converting structure may be disposed in the path of light extracted from the LED. The wavelength converting structure includes one or more wavelength converting materials which may be, for example, conventional phosphors, organic phosphors, quantum dots, organic semiconductors, II-VI or III-V semiconductors, II-VI or III-V semiconductor quantum dots or nanocrystals, dyes, polymers, or other materials that luminesce. The wavelength converting material includes light scattering or light diffusing elements, such as titanium dioxide (TiO2), absorbs light emitted by the LED, and emits light of one or more different wavelengths. The light provided by the light source may be white, polychromatic, or monochromatic.

<FIG> illustrates, by way of example, a partial cross-section diagram of an embodiment of a display device <NUM>, not forming part of the claimed invention, that includes a backlight. The display device <NUM> includes the display screen <NUM>, the light guide <NUM>, and the light emitting element <NUM>. The display screen <NUM>, can include an LCD screen in accordance with one embodiment. The LCD screen can be part of a television, a computer monitor, a smartphone screen, a watch screen, calculator screen, or other screen.

The light emitting element <NUM> can transmit light towards the light guide <NUM>. The light emitting element <NUM> can include a light emitting diode (LED), a cold-cathode fluorescent lamp (CCFL), or the like. Theoretically, the light emitting element <NUM> can produce light with a Lambertian or near Lambertian distribution. The light emitting element <NUM> can include a top coating <NUM> and a side coating.

The display device <NUM> further includes a backplate <NUM>, reflector sheets <NUM>, <NUM>, and a substrate <NUM>. The backplate <NUM> provides protection from an external environment for the reflector sheets <NUM>, <NUM>, the light emitting element <NUM>, the substrate <NUM>, the light guide <NUM>, and a surface of the display screen <NUM> facing the light guide <NUM>. The backplate <NUM> can be made of metal, ceramic, polymer, or the like. An extent that the backplate <NUM> extends over the top surface <NUM> of the light guide <NUM> is sometimes called a bezel.

The reflector sheet <NUM>, <NUM> is made of a light scattering and highly reflective material. The reflective material can reflect <NUM>%, <NUM>%, <NUM>%, more or less light, or some value therebetween, of the light incident thereon. The reflector sheet <NUM>, <NUM> can be patterned to help scatter the light or reflect the light to a specified location.

The top coating <NUM> can alter a color of the light from the light emitting element <NUM>. For example, if the top coating <NUM> is phosphor, the light emitted from the light emitting element <NUM> can appear whiter to the human eye. This is because phosphor absorbs some of the blue light emitted from the light emitting element <NUM>.

The side coating <NUM> can be made of a wide scattering, highly reflective material (e.g., above <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, or some percentage therebetween of reflection at a wavelength of the light emitting element <NUM>). The side coating <NUM> can help ensure that more light is transmitted through the top coating <NUM> or towards the light guide <NUM>. Examples of side coating materials include filled silicon, acrylic, a white plastic, or other dielectric coating.

The substrate <NUM> can provide power and circuit routing for the light emitting element <NUM>. The light emitting element <NUM> can be electrically and mechanically connected to electrical power through a trace or other electrical interconnect on or in the substrate <NUM>. The substrate <NUM> can include a flex or rigid printed circuitry board (PCB). A flex PCB can be made of polyimide, polydimethylsiloxane, or the like. A rigid PCB can be made of FR-<NUM>, prepreg, or the like.

The light guide <NUM> is designed to spread the light from the light emitting element <NUM> as uniformly as possible across the display screen <NUM>. The transmission of light on the display screen <NUM>, depend on the polarization of incident light. The display screen transmission is maximum for a specific polarization. Further, newly emerging LGPs with diffractive patterns require polarized light for optimum performance. Example embodiments provide solutions to control polarization of the light incident on the display screen <NUM>.

Polarization is defined relative to the plane of incidence. The plane of incidence is a plane that contains incoming rays and reflected rays, as well as, a normal to a sample surface. Perpendicular (s-) polarization is the polarization where the electric field is perpendicular to the plane of incidence, while parallel (p-) polarization is the polarization where the electric field is parallel to the plane of incidence.

Different polarizations of light can also be absorbed to different degrees by different materials. This is an important property for LCD screens. (e.g., the display screen <NUM>) It is beneficial to have as little light absorbed by the material of the LCD screen as possible. This can be limited by polarizing the light incident on the light guide panel (e.g., light guide <NUM>), and ultimately the LCD screen.

Incandescent, fluorescent, LED, and many other light sources are randomly polarized. An LCD screen has two (or more) layers of polarization material on top of each other. Normally, both layers are polarized in the same way, so that light passes through both layers. One (or both) of the layers can be made of liquid crystals. A polarization of a liquid crystal changes based on an applied voltage. When the voltage is applied, the polarization of the crystal can shift so that it is at <NUM> degrees difference from what it was before the voltage was applied. This creates an area that does not permit light therethrough. Different areas of liquid crystals can be controlled by voltages from control circuitry.

Liquid crystals are generally thin, rod-like molecules that move in response to an applied voltage. In a display, there are many liquid crystals and generally not all of them have exactly the same orientation with respect to another, but they are generally pointed in more or less the same direction. The liquid crystals turn and move in response to the voltage, such as to be in another orientation.

Based on the direction in which the liquid crystals point, compared to a polarization of incoming light and a thickness of the liquid crystals, the polarization of the incoming light either gets (a) rotated by <NUM> degrees while passing through the liquid crystals or (b) not rotated at all, in accordance with some embodiments. One can take advantage of this polarization rotation with the use of polarizers. Placing a polarizer on the output of the liquid crystal allows light to be let through only when the polarization of the light matches the polarization orientation of the polarizer. For example, turning the voltage on, rotates the liquid crystals one way and light gets through. Turning the voltage off stops light from getting through, or vice versa.

By placing the liquid crystals molecules into pixel format and putting color (e.g., red, green, blue, or combination thereof) filters over them, color can be provided. Some LCDs, like a basic digital watch, do not have a "backlight" and color filters, and therefore produce only a black and a greyish background. These watches rely on ambient light to pass through the liquid crystals. Many LCD displays, however, have backlights. Backlights help provide vibrant color incorporation (by allowing RGB filters to transmit a lot of light) and high brightness levels.

To increase the efficiency of the LCD backlight, polarized light can be beneficial. As previously discussed, the polarized light can have better reflection characteristics and can be absorbed less by a material in the LCD screen. For at least these reasons, it is desired to control the polarization of the light incident on the LGP and ultimately the LCD screen.

However, simply adding a polarizer between the LED and the LGP increases the bezel length of the display. Also, for thermal management, it is beneficial to mount the LEDs on a separate PCB from the polarizer.

Example embodiments include a new design for edge coupling and polarizing of the emission (e.g., Lambertian emission) from the light emitting element <NUM> to the light guide <NUM>. Example embodiments can include a modified version of Polarizing Beam Splitter (PBS). The design of example embodiments is compact and can reduce the bezel length (as compared to other polarized solutions) by folding the LED coupling path. Also, example embodiments can simplify the thermal management of LEDs since they can be mounted on a larger circuit board. The circuit board can be oriented so that a major surface (a surface on which the light emitting element <NUM> is mounted) faces the screen <NUM>. This orientation is about <NUM> degrees from a normal orientation of a light emitting element <NUM>.

3D displays based on lightfield technology rely on diffraction from a Diffractive Optical Element (DOE) pattern on the top surface <NUM> of the light guide <NUM>. In many 3D displays, the light is edge coupled from the edges of the light guide <NUM> and into the light guide <NUM>. On top of the light guide <NUM>, a liquid crystal panel (e.g., the screen <NUM>) modifies the spatial distribution of the light by switching pixels on and off. The incident light on the liquid crystal panel and inside the light guide <NUM> can be polarized to maximize the power efficiency of the display and brightness of light emitted by the screen <NUM>.

<FIG> illustrates a diagram of an embodiment of a display device <NUM>, according to the claimed invention, that provides s polarized light to the screen <NUM>. The display device <NUM> as illustrated includes the backplate <NUM>, the reflector sheet <NUM>, the substrate <NUM>, the light emitting element <NUM>, the side coating <NUM>, the top coating <NUM>, a polarizing device, and the display screen <NUM>. The polarizing device includes prisms <NUM>, <NUM>, mirrors <NUM>, <NUM>, and a film <NUM>.

The polarizing device polarizes unpolarized light <NUM> from the light emitting element <NUM>. The light <NUM> is received through a receiving surface <NUM>. The polarizing device emits polarized light <NUM> towards the light guide <NUM> through a transmission surface <NUM>.

The light from the receiving surface <NUM> is incident on the prism <NUM>. A prism (e.g., prism <NUM>, <NUM>) is a mostly transparent optical element (at specified wavelengths) that refracts light. The prism generally has a polyhedral shape. A prism with a triangular base has a shape known as a triangular prism. The triangular prism includes sides that share an edge with, and are connected by, a hypotenuse. The sides and the hypotenuse are generally planar, generally rectangular, and generally flat. The sides and hypotenuse are connected by two generally parallel faces called bases.

From an unpolarized light <NUM>, s polarization is reflected by film <NUM> as polarized light <NUM> to the light guide <NUM>. The remainder of the unpolarized light <NUM> is transmitted as ray <NUM> with polarization p. Mirror <NUM> reflects back light <NUM> as light <NUM> which is partially reflected as polarization s shown by ray <NUM> and mainly transmitted through the film <NUM> with polarization p shown by ray <NUM>. Ray <NUM> scatters from layer <NUM> and loses its polarization and recycles as unpolarized light <NUM>. Ray <NUM> is reflected back as <NUM> and experiences partial reflection as ray <NUM> and partial transmission as polarized light <NUM>. The film <NUM> can be made of a polyester, epoxy, or urethane-based adhesive, a combination thereof, among others. The film <NUM> can include a multilayer structure. The film <NUM> can include a layer of adhesive and alternating layers of high and low refractive index materials for polarization modification. The film <NUM> can operate using Brewster's angle in each layer to separate orthogonal polarization components of light.

The light <NUM>, <NUM> is reflected off the mirrors <NUM>, <NUM>, respectively as the light <NUM>, <NUM>. The light <NUM>, <NUM> is again incident on the film <NUM> and a portion of the light <NUM>, <NUM> that is polarized in the specified manner is transmitted as the light <NUM>. Another portion of the light <NUM>, <NUM> is guided to the top coating <NUM>.

The light <NUM> is recycled to the top coating <NUM> and randomized. The recycled light with randomized polarization is again incident on the prism <NUM> and gains the appropriate polarization and emission through the transmission surface <NUM> as light <NUM> that is mostly polarized (over <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, more, or some percentage therebetween).

The orientation of the substrate <NUM> and the light emitting element <NUM> relative to the light guide <NUM> are different than normal. <FIG> shows a typical orientation between the light emitting element <NUM> and the light guide <NUM> in accordance with an example embodiment. Typically, the light emitting element <NUM> transmits light directly towards an input surface <NUM> of the light guide <NUM>. In the embodiment of <FIG>, however, the light emitting element <NUM> emits light generally perpendicular to the input surface <NUM> and the polarizing device redirects the light <NUM> to the input surface <NUM>. In other words, in <FIG>, the light emitting element <NUM> is oriented to transmit the light <NUM> towards the display screen <NUM>. The light <NUM> from the light emitting element <NUM> is polarized and redirected by the polarizing device to the light guide <NUM>.

Not only does the embodiment in <FIG> provide polarized light, it also allows for improved thermal management of the light emitting element <NUM> and other components of the display device <NUM>. The improved thermal management can be from increased space for heat dissipating components. The heat dissipating components can be on the substrate <NUM>. A depth of the backplate <NUM> (indicated by arrow <NUM>) is generally smaller than the width of the bezel (indicated by arrow <NUM>) at a front of the display device <NUM>. By allowing the substrate <NUM> to substantially span the width of the bezel (indicated by arrow <NUM>), a larger heat dissipating component can be used, as compared to a size of a heat dissipating component that, at biggest, spans a thickness (e.g., the dimension indicated by the arrow <NUM>) of the backplate <NUM>. However, improved thermal management of the display device <NUM> may cause the system to be slightly thicker (e.g., the dimension corresponding to the arrow <NUM>) than other polarizer solutions, such as that illustrated in <FIG>.

<FIG> illustrates a diagram of an embodiment of a display device <NUM>, according to the claimed invention, with an improved backlight. The display device <NUM> is similar to the display device <NUM>, with the display device <NUM> including a different polarizing device <NUM>. The polarizing device <NUM> of the display device <NUM> is configured to polarize light with s polarization similar to display device <NUM>. The polarizing device <NUM> will be discussed in more detail below.

<FIG> illustrates a diagram of a portion of the display device <NUM> with a view of the polarizing device <NUM> indicated by arrow labelled "<NUM>" in <FIG>. The polarizing device <NUM> as illustrated includes three prisms <NUM>, <NUM>, <NUM>. The prism <NUM> is coupled at a first side to a hypotenuse of the prism <NUM>. The prism <NUM> is coupled at a second side to a hypotenuse of the prism <NUM>. A hypotenuse of the prism <NUM> faces the input surface <NUM> of the light guide <NUM>.

The polarizing device <NUM> polarizes unpolarized light <NUM> from the light emitting element <NUM>. The light <NUM> is received through a receiving surface <NUM> of the polarizing device <NUM>. The polarizing device <NUM> emits polarized light <NUM> towards the light guide <NUM> through a transmission surface <NUM>.

The light from the receiving surface <NUM> is incident on the prisms <NUM>, <NUM>, <NUM>. The prisms <NUM>, <NUM>, <NUM> can include a birefringent crystalline material.

A portion of the light <NUM> that is polarized (either s or p polarization) is transmitted out the transmission surface <NUM>. Another portion of the light <NUM> is incident on a film <NUM> and reflected to the prism <NUM>, <NUM> as the light <NUM>. The film <NUM> can be an adhesive that connects the prisms <NUM>, <NUM>, <NUM>. The film <NUM> can be similar to the film <NUM>.

The light <NUM> is reflected off the mirror <NUM> as the light <NUM>. The light <NUM> is again incident on the film <NUM> and a portion of the light <NUM> that is polarized in the specified manner is transmitted as the light <NUM>. Another portion of the light <NUM> is guided to the top coating <NUM>.

The light <NUM> is recycled to the top coating <NUM> and randomized. The recycled light with randomized polarization is again incident on the prism <NUM>, <NUM> and gains the appropriate polarization for emission out the transmission surface <NUM> as light <NUM> that is mostly polarized (over <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, more, or some percentage therebetween).

The mirror <NUM> can surround the prisms <NUM>, <NUM>, <NUM>, leaving the transmission surface <NUM> and the receiving surface <NUM> exposed. The mirror <NUM> can be similar to the mirror <NUM>, <NUM>. The display device <NUM> is a thinner device with a slightly increased bezel length as compared to the display device <NUM>.

<FIG> illustrates a diagram of an embodiment of a display device <NUM>, according to the claimed invention, that provides p polarized light to the screen <NUM>. The display device <NUM> as illustrated includes the backplate <NUM>, the reflector sheet <NUM>, <NUM>, the substrate <NUM>, the light emitting element <NUM> (including the side coating <NUM> and the top coating <NUM> not labelled in <FIG>), a polarizing device, and the display screen <NUM>. The polarizing device includes prisms <NUM>, <NUM>, mirror <NUM> and a film <NUM>.

The polarizing device polarizes unpolarized light <NUM> from the light emitting element <NUM>. The light <NUM> is received through a receiving surface <NUM>. The polarizing device emits p polarized light <NUM> towards the input surface <NUM> of the light guide <NUM> through a transmission surface <NUM>.

The light from the receiving surface <NUM> is incident on the prism <NUM>. The prism <NUM>, <NUM> can be similar to other prisms discussed. From an unpolarized light <NUM>, p polarized light is transmitted by film <NUM> as p polarized light <NUM> to the light guide <NUM>. The film <NUM> can be similar to other films discussed. The remainder of the unpolarized light <NUM> is transmitted as light <NUM>, <NUM> with mostly s polarization.

The light <NUM>, <NUM> is reflected off the mirror <NUM> as the light <NUM>, <NUM>, respectively. The light <NUM>, <NUM> is again incident on the film <NUM> and a portion of the light <NUM>, <NUM> that is p polarized is transmitted as the light <NUM>. Another portion of the light <NUM>, <NUM> is guided to the top coating <NUM> as light <NUM>.

<FIG> illustrates a diagram of a portion of a display device <NUM>, according to the claimed invention, that provides p polarized light to the screen <NUM>. The polarizing device as illustrated includes three prisms <NUM>, <NUM>, <NUM>. The prism <NUM> is coupled at a first side to a hypotenuse of the prism <NUM>. The prism <NUM> is coupled at a second side to a hypotenuse of the prism <NUM>. A hypotenuse of the prism <NUM> faces the input surface <NUM> of the light guide <NUM>.

The polarizing device polarizes unpolarized light <NUM> from the light emitting element <NUM>. The light <NUM> is received through a receiving surface <NUM> of the polarizing device. The polarizing device emits polarized light <NUM> towards an input surface <NUM> of the light guide <NUM> through a transmission surface <NUM>.

The light from the receiving surface <NUM> is incident on the prisms <NUM>, <NUM>, <NUM>. A portion of the light <NUM> that is polarized (p polarized) is transmitted out the transmission surface <NUM>. Another portion of the light <NUM> is incident on a film <NUM> and reflected to the prism <NUM>, <NUM> as the light <NUM>. The film <NUM> can be an adhesive that connects the prisms <NUM>, <NUM>, <NUM>. The film <NUM> can be similar to the film <NUM>.

The light <NUM> is reflected off the mirror <NUM> as the light <NUM>. The light <NUM> is again incident on the film <NUM> and a portion of the light <NUM> that is p polarized is transmitted as the light <NUM>. Another portion of the light <NUM> is guided to the top coating <NUM>.

The light <NUM> is recycled to the top coating <NUM> and its polarization is randomized by the top coating <NUM>. The recycled light with randomized polarization is again incident on the prism <NUM>, <NUM> and gains the appropriate polarization for emission out the transmission surface <NUM> as light <NUM> that is mostly p polarized (over <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, more, or some percentage therebetween).

<FIG> shows a flow chart of an example of a method <NUM> for forming a light-emitting apparatus, in accordance with some examples, not forming part of the claimed invention. The method <NUM> can be used to form any of the example apparatuses of <FIG>, among other apparatuses. The method <NUM> is but one method for forming a light-emitting apparatus; other suitable methods can also be used.

The method <NUM> can include coupling a visible light-emitting element to a circuit board and in a bezel of a backplate, at operation <NUM>, situating a light guide panel including an input surface and a transmission surface, the transmission surface generally perpendicular to the input surface, such that the input surface faces the light-emitting element, at operation <NUM>; and situating a polarizing device, including a prism, to receive visible light from the light-emitting element, polarize the visible light, and transmit the polarized light to the input surface of the light guide panel, at operation <NUM>.

The polarizing device can include two exposed surfaces, four non-exposed surfaces, and a reflecting component on the non-exposed surfaces. The method <NUM> can include, wherein the two exposed surfaces comprises a first surface facing the light emitting element, and a second surface facing the input surface of the light guide panel. The method <NUM> can include, wherein the first surface is generally perpendicular to the second surface and the polarized light is s-polarized. The method <NUM> can include, wherein the first surface is generally parallel to the second surface and the polarized light is p-polarized.

While the preceding discussion regards polarization in a backlight application, the same polarizing device can be used in other applications. For example, the polarizing device can be used in an outdoor lighting fixture, such as a streetlight. The polarized light can reduce reflection at (wet) planar surfaces, for example. In another example, the backlight can be used in an extended reality (XR) application (e.g., an augmented reality (AR), virtual reality (VR), or mixed reality (MR) application).

<FIG> shows a display system <NUM> in accordance with some embodiments, not forming part of the claimed invention. The system <NUM> includes an XR system <NUM>, such as can be part of a communication or computing device (e.g., smart phone, tablet/laptop computer) or another device, such as a projector. The LED array <NUM> can be similar to the foregoing described embodiments and can include multiple sets of LEDs driven by an LED driver <NUM> that is controlled by a controller <NUM>, such as a microprocessor. In some embodiments the controller <NUM> can be coupled to the XR system <NUM> and sensors <NUM> and operate in accordance with instructions and profiles stored in a memory <NUM>. In some embodiments, the system <NUM> can include modules that allow wirelessly communicating via Bluetooth, WiFi, long term evolution (LTE), or any other communication protocol using transceiver circuitry.

The XR system <NUM> can incorporate a wide range of optics and optical reflective or transmissive surfaces. In some embodiments, optics can be used to correct or minimize two-or three dimensional optical errors including pincushion distortion, barrel distortion, longitudinal chromatic aberration, spherical aberration, chromatic aberration, field curvature, astigmatism, or any other type of optical error. In some embodiments, optical elements can be used to magnify and/or correct images. Optical elements can include apertures, filters, a Fresnel lens, a convex lens, a concave lens, or any other suitable optical element that affects the projected. Additionally, one or more of the optical elements can have one or more coatings, including ultraviolet (UV) blocking or anti-reflective coatings. In some embodiments, magnification of display images allows the XR system <NUM> to be physically smaller, of less weight, and require less power than larger displays. Additionally, magnification can increase a field of view of the displayed content allowing display presentation equals a user's normal field of view.

In one embodiment the LED driver <NUM> can be formed, for example, using either an analog-driver approach or a pulse-width modulation (PWM)- driver approach. When an analog driver is used, all LED sets that are driven together may be driven simultaneously. Each LED or LED set may be driven independently by providing a different current for each LED or LED set. In a PWM driver, each LED or LED set may be switched on, in sequence, at high speed and driven with substantially the same current. The color of the display may be controlled by changing the duty cycle of each color. In some embodiments, the current is supplied from a voltage-controlled current source.

The amount of current supplied and/or duty cycle may be controlled, as indicated above, by the controller <NUM>. The controller <NUM> may be a microprocessor that includes, for example, an application processor and a baseband processor. Sensors <NUM> may include, for example, positional sensors (e.g., a gyroscope and/or accelerometer) and/or other sensors that may be used to determine the position, speed, and orientation of system <NUM>. The signals from the sensors <NUM> may be supplied to the controller <NUM> to be used to determine the appropriate course of action of the controller <NUM> (e.g., which image should be presented to an XR user).

The memory <NUM> may be nonvolatile memory. The memory <NUM> may store instructions and applications used by the controller <NUM> to control driving of the LED array by the driver <NUM> based on particular profiles also stored therein. The instructions may take into account input from the various sensors <NUM> as well as images to be streamed, overlain, or otherwise supplied to the XR user.

The controller <NUM> may be any microprocessor capable of executing instructions (sequential or otherwise) that specify actions to be taken. The system <NUM> may contain logic and various components and modules on which the controller <NUM> may operate, as described above. Modules and components are tangible entities (e.g., hardware) capable of performing specified operations and may be configured or arranged in a certain manner. In an example embodiment, circuits may be arranged (e.g., internally or with respect to external entities such as other circuits) in a specified manner as a module. The controller <NUM> may be configured by firmware or software (e.g., instructions, an application portion, or an application) as a module that operates to perform specified operations. In an example embodiment, the software may reside on a machine readable medium, such as a non-statutory machine readable medium. In an example embodiment, the software, when executed by the underlying hardware of the module, causes the hardware to perform the specified operations.

Accordingly, the term "module" (and "component") is understood to encompass a tangible entity, be that an entity that is physically constructed, specifically configured (e.g., hardwired), or temporarily (e.g., transitorily) configured (e.g., programmed) to operate in a specified manner or to perform part or all of any operation described herein. Software may, accordingly, configure a hardware processor, for example, to constitute a particular module at one instance of time and to constitute a different module at a different instance of time.

In operation, in some embodiments, illumination from all of the pixels of the LED assembly <NUM> may be adjusted - deactivated or the intensity of illumination of the pixels may be reduced by a significant predetermined percent (e.g., between about <NUM>% and about <NUM>%). In various embodiments, the adjustment may occur for a predetermined amount of time or until manually overridden. Regardless of whether illumination from all, or merely some, of the pixels of the LED assembly <NUM> are adjusted, illumination from some or all of the other pixels (within the same LED array, if present, or in the separate LED array) may or may not also be adjusted. That is, some or all the other pixels, may be activated, if inactive when the pixels are active, the intensity of illumination of the other pixels may be increased by a significant predetermined percent (e.g., between about <NUM>% and about <NUM>%), or the intensity of illumination of the other pixels may be unaffected by adjustment of the pixels. In the latter case, the other pixels may thus provide light at the same time and in the same place as light from the pixels.

Claim 1:
A display device (<NUM>; <NUM>; <NUM>; <NUM>), comprising:
a light emitting element (<NUM>) comprising a top coating (<NUM>) and a side coating (<NUM>), configured to emit visible light (<NUM>; <NUM>; <NUM>; <NUM>);
a polarizing device situated to receive unpolarized visible light (<NUM>; <NUM>; <NUM>; <NUM>) emitted by the light emitting element (<NUM>) and to generate polarized light (<NUM>; <NUM>; <NUM>; <NUM>), the polarizing device including a receiving surface (<NUM>; <NUM>; <NUM>; <NUM>) and a transmission surface (<NUM>; <NUM>; <NUM>; <NUM>), the receiving surface (<NUM>; <NUM>; <NUM>; <NUM>) facing the light emitting element (<NUM>), wherein the polarizing device comprises:
- a plurality of prisms (<NUM>, <NUM>; <NUM>, <NUM>, <NUM>; <NUM>, <NUM>; <NUM>, <NUM>, <NUM>),
- a mirror (<NUM>, <NUM>; <NUM>; <NUM>; <NUM>) arranged to surround the prisms (<NUM>, <NUM>; <NUM>, <NUM>, <NUM>; <NUM>, <NUM>; <NUM>, <NUM>, <NUM>), leaving the transmission surface (<NUM>; <NUM>; <NUM>; <NUM>) and the receiving surface (<NUM>; <NUM>; <NUM>; <NUM>) exposed, and
- a film (<NUM>; <NUM>; <NUM>; <NUM>) between prisms (<NUM>, <NUM>; <NUM>, <NUM>, <NUM>; <NUM>, <NUM>; <NUM>, <NUM>, <NUM>); and
wherein a portion of the light (<NUM>; <NUM>; <NUM>; <NUM>) reflected by the mirror (<NUM>, <NUM>; <NUM>; <NUM>; <NUM>) and transmitted by the film (<NUM>; <NUM>; <NUM>; <NUM>) is recycled to the top coating (<NUM>) and randomized, and wherein the recycled light with randomized polarization is again incident on a prism (<NUM>, <NUM>; <NUM>, <NUM>, <NUM>; <NUM>, <NUM>; <NUM>, <NUM>, <NUM>) of the polarizing device;
a light guide panel (<NUM>) configured to receive the polarized light (<NUM>; <NUM>; <NUM>; <NUM>) at an input surface (<NUM>) facing the transmission surface (<NUM>; <NUM>; <NUM>; <NUM>) of the polarizing device and to distribute the polarized light (<NUM>; <NUM>; <NUM>; <NUM>) to a major surface (<NUM>) of the light guide panel (<NUM>) facing a display screen (<NUM>) of the display device (<NUM>; <NUM>;<NUM>; <NUM>).