Abstract: A head mounted display device includes a display panel and a lens assembly mounted so that an optical axis of the lens assembly intersects the display panel. The lens assembly includes a lens body having a surface facing the display panel and defining Fresnel prisms. A Fresnel prism of the Fresnel prisms has a first facet angle when viewed in a first cross-section and has a second facet angle when viewed in a second cross-section parallel to the first cross-section. The first facet angle is different than the second facet angle.

Abstract: Systems and methods that employ a near-eye display system including an optical assembly are described. The optical assembly may include a head-mounted display device worn by a user in which the head-mounted display device adapted to house an image projecting device and an optical assembly. The optical assembly may include, for at least one eyepiece, a first flat filter stack operable to be oriented in a first direction. and a second flat filter stack operable to be oriented in a second direction. The near-eye display system assembly may also include a display panel adapted to receive image content from the image projecting device, wherein the display panel is adapted to be oriented in the second direction.

Abstract: Systems and methods are described for receiving image content from an emissive display toward a first filter stack, the first filter stack adapted to be oriented in a first direction from an optical axis of a first lens, and toward the first lens, transmitting the image content through a curved lens parallel to the optical axis of the first lens, wherein the curved lens transmits a portion of the image content to at least one optical element and to a second filter stack, the second filter stack being adapted to be oriented in a second direction from the optical axis of the first lens, and receiving the portion from the second filter stack and providing at least some of the portion to the first lens for viewing by a user.

Abstract: Very thin flash modules for cameras are described that do not appear as a point source of light to the illuminated subject. Therefore, the flash is less objectionable to the subject. In one embodiment, the light emitting surface area is about 5 mm×10 mm. Low profile, side-emitting LEDs optically coupled to solid light guides enable the flash module to be thinner than 2 mm. The flash module may also be continuously energized for video recording. The module is particularly useful for cell phone cameras and other thin cameras.

Abstract: A semiconductor structure including a light emitting layer disposed between an n-type region and a p-type region and a photonic crystal formed within or on a surface of the semiconductor structure is combined with a ceramic layer which is disposed in a path of light emitted by the light emitting layer. The ceramic layer is composed of or includes a wavelength converting material such as a phosphor.

Abstract: Backlights containing low profile, side-emitting LEDs are described that have improved brightness uniformity. In one embodiment, the backlight comprises a solid transparent lightguide with a plurality of openings in a bottom surface of the lightguide, each opening containing a side-emitting LED. Prisms or other optical features are formed in the top wall of each opening to reflect light in the lightguide towards a light output surface of the lightguide so that the side-emitting LEDs do not appear as dark spots at the output of the backlight. To avoid any direct emission from the sides of the LED toward the output surface of the lightguide appearing as bright areas, optical features are formed at the edges of the opening or in the output surface of the lightguide so that direct emission light is not output from the lightguide. Substantially identical cells may be formed in the lightguide using cellular walls around one or more LEDs.

Abstract: Low profile, side-emitting LEDs are described that generate white light, where all light is emitted within a relatively narrow angle generally parallel to the surface of the light-generating active layer. The LEDs enable the creation of very thin backlights for backlighting an LCD. In one embodiment, the LED emits blue light and is a flip chip with the n and p electrodes on the same side of the LED. Separately from the LED, a transparent wafer has deposited on it a red and green phosphor layer. The phosphor color temperature emission is tested, and the color temperatures vs. positions along the wafer are mapped. A reflector is formed over the transparent wafer. The transparent wafer is singulated, and the phosphor/window dice are matched with the blue LEDs to achieve a target white light color temperature. The phosphor/window is then affixed to the LED.

Abstract: Various embodiments of corner-coupled backlights are described, where one or more white light LEDs are optically coupled to a truncated corner edge of a solid rectangular light guide backlight. The one or more LEDs are mounted in a small reflective cavity, whose output opening is coupled to the truncated corner of the light guide. The reflective cavity provides a more uniform light distribution at a wide variety of angles to the face of the truncated corner to better distribute light throughout the entire light guide volume. To enable a thinner light guide, the LED die is positioned in the reflective cavity so that the major light emitting surface of the LED is parallel to the top surface of the light guide. The reflective cavity reflects the upward LED light toward the edge of the light guide.

Abstract: A substantially hemispherical lens surrounding an LED die is described that creates a sparkle as an observer views the lens from different angles. The lens is formed of an interconnected array of 100-10,000 or more lenslets. Each lenslet focuses an image of the LED die at an output of the lenslet such that the LED die image area at the output is less than 1/9 the area of the LED die to create a substantially point source image of the LED die at an outer surface of the lens. When the LED die is energized, the shape of each lenslet causes point source images of the LED die to be perceived by an observer at various viewing angles, such that the emitted LED light appears to sparkle and speckle as the observer moves relative to the lens.

Abstract: A double-molded lens for an LED includes an outer lens molded around the periphery of an LED die and a collimating inner lens molded over the top surface of the LED die and partially defined by a central opening in the outer lens. The outer lens is formed using silicone having a relatively low index of refraction such as n=1.33-1.47, and the inner lens is formed of a higher index silicone, such as n=1.54-1.76, to cause TIR within the inner lens. Light not internally reflected by the inner lens is transmitted into the outer lens. The shape of the outer lens determines the side emission pattern of the light. The front and side emission patterns separately created by the two lenses may be tailored for a particular backlight or automotive application.

Abstract: A backlight for a color LCD includes white light LEDs formed using a blue LED die with a layer of red and green phosphors over it. The attenuation by the LCD layers of the blue light component of the white light is typically greater as the blue wavelength becomes shorter. In order to achieve a uniform blue color component across the surface of an LCD screen and achieve uniform light output from one LCD to another, the blue light leakage of the phosphor layer is tailored to the dominant or peak wavelength of the blue LED die. Therefore, the white points of the various white light LEDs in a backlight should not match when blue LED dies having different dominant or peak wavelengths are used in the backlight. The different leakage amounts through the tailored phosphor layers offset the attenuation vs. wavelength of the LCD layers.

Abstract: A low profile side-emitting lens for an LED die has two tiers of different waveguides radially extending out from a center side-emitting lens. An LED emits light into the center side-emitting lens, which has a curved surface that internally reflects the LED light outward approximately parallel to the top surface of the LED die. The center lens has a height of 2 mm, required for reflecting the LED light outward. Radially extending from the periphery of the bottom half of the center lens is a bottom tier of waveguides, each having a height of 1 mm, and radially extending from the periphery of the top half of the center lens is a top tier of waveguides, each having a height of 1 mm. The light output areas of the top and bottom tiers of waveguides are parallel with each other so that the 2 mm high side emission is reduced to a 1 mm side emission without reducing the emission area.

Abstract: A substantially hemispherical lens surrounding an LED die is described that creates a sparkle as an observer views the lens from different angles. The lens is formed of an interconnected array of 100-10,000 or more lenslets. Each lenslet focuses an image of the LED die at an output of the lenslet such that the LED die image area at the output is less than 1/9 the area of the LED die to create a substantially point source image of the LED die at an outer surface of the lens. When the LED die is energized, the shape of each lenslet causes point source images of the LED die to be perceived by an observer at various viewing angles, such that the emitted LED light appears to sparkle and speckle as the observer moves relative to the lens.

Abstract: A method of forming a light emitting diode (LED) module molds an array of lens support frames over an array of connected lead frames. LEDs are bonded to the lead frame contacts within the support frames. Molded lenses are then affixed over each support frame, and the lead frames are diced to create individual LED modules. In another embodiment, the lenses are molded along with the support frames to create unitary pieces, and the support frames are affixed to the lead frames in the array of connected lead frames. In another embodiment, no lenses are used, and cups are molded with the lead frames so that the LED module is formed solely of the unitary lead frame/cup and the LED. Since each LED enclosure is formed of only one or two separate pieces, and the modules are fabricated on an array scale, the modules can be made very small and simply.

Abstract: Backlights containing low profile, side-emitting LEDs are described that have improved brightness uniformity. In one embodiment, the backlight comprises a solid transparent lightguide with a plurality of openings in a bottom surface of the lightguide, each opening containing a side-emitting LED. Prisms or other optical features are formed in the top wall of each opening to reflect light in the lightguide towards a light output surface of the lightguide so that the side-emitting LEDs do not appear as dark spots at the output of the backlight. To avoid any direct emission from the sides of the LED toward the output surface of the lightguide appearing as bright areas, optical features are formed at the edges of the opening or in the output surface of the lightguide so that direct emission light is not output from the lightguide. Substantially identical cells may be formed in the lightguide using cellular walls around one or more LEDs.

Abstract: Amber light LEDs have a higher luminance than red light LEDs. A vast majority of images displayed on television consists of colors that can be created using amber, green and blue components, with only a small percentage of red. In one embodiment of the present invention, the typically red primary light source in a projection display system is augmented with an amber light source. Green and blue primary light sources are also provided. All the light sources are high power LEDs. The particular mixture of the red and amber light is accomplished by varying the duty cycles of the red LEDs and the amber LEDs. If the RGB image to be displayed can be created using a higher percentage of amber light and a lower percentage of red light, the duty cycle of the amber LEDs is increased while the duty cycle of the red LEDs is decreased. Light/pixel modulators for creating the full color image from the three primary light sources are controlled to compensate for the variable amber/red mixture.

Abstract: A double-molded lens for an LED includes an outer lens molded around the periphery of an LED die and a collimating inner lens molded over the top surface of the LED die and partially defined by a central opening in the outer lens. The outer lens is formed using silicone having a relatively low index of refraction such as n=1.33-1.47, and the inner lens is formed of a higher index silicone, such as n=1.54-1.76, to cause TIR within the inner lens. Light not internally reflected by the inner lens is transmitted into the outer lens. The shape of the outer lens determines the side emission pattern of the light. The front and side emission patterns separately created by the two lenses may be tailored for a particular backlight or automotive application.

Abstract: A low profile side-emitting lens for an LED die has two tiers of different waveguides radially extending out from a center side-emitting lens. An LED emits light into the center side-emitting lens, which has a curved surface that internally reflects the LED light outward approximately parallel to the top surface of the LED die. The center lens has a height of 2 mm, required for reflecting the LED light outward. Radially extending from the periphery of the bottom half of the center lens is a bottom tier of waveguides, each having a height of 1 mm, and radially extending from the periphery of the top half of the center lens is a top tier of waveguides, each having a height of 1 mm. The light output areas of the top and bottom tiers of waveguides are parallel with each other so that the 2 mm high side emission is reduced to a 1 mm side emission without reducing the emission area.

Abstract: A white light LED for use in backlighting or otherwise illuminating an LCD is described where the white light LED comprises a blue LED over which is affixed a preformed red phosphor platelet and a preformed green phosphor platelet. In one embodiment, to form a platelet, a controlled amount of phosphor powder is placed in a mold and heated under pressure to sinter the grains together. The platelet can be made very smooth on all surfaces. A UV LED may also be used in conjunction with red, green, and blue phosphor plates. The LED dies vary in color and brightness and are binned in accordance with their light output characteristics. Phosphor plates with different characteristics are matched to the binned LEDs to create white light LEDs with a consistent white point for use in backlights for liquid crystal displays.

Abstract: A backlight for a color LCD includes white light LEDs formed using a blue LED die with a layer of red and green phosphors over it. The attenuation by the LCD layers of the blue light component of the white light is typically greater as the blue wavelength becomes shorter. In order to achieve a uniform blue color component across the surface of an LCD screen and achieve uniform light output from one LCD to another, the blue light leakage of the phosphor layer is tailored to the dominant or peak wavelength of the blue LED die. Therefore, the white points of the various white light LEDs in a backlight should not match when blue LED dies having different dominant or peak wavelengths are used in the backlight. The different leakage amounts through the tailored phosphor layers offset the attenuation vs. wavelength of the LCD layers.