A light emitting device includes a first substrate, a second substrate and a plurality of micro epitaxial structures. The second substrate is disposed opposite to the first substrate. The micro epitaxial structures are periodically disposed on the substrate and located between the first substrate and the second substrate. A coefficient of thermal expansion of the first substrate is CTE1, a coefficient of thermal expansion of the second substrate is CTE2, a side length of each of the micro epitaxial structures is W, W is in the range between 1 micrometer and 100 micrometers, and a pitch of any two adjacent micro epitaxial structures is P, wherein W/P=0.1 to 0.95, and CTE2/CTE1=0.8 to 1.2.

Techniques for supplying auxiliary power to lighting driver circuitry are disclosed. An auxiliary power supply can be used, for example, to provide auxiliary power to a current source that drives an LED string. In some embodiments, the LED string is effectively used as a series resistor to charge a capacitor that provides the auxiliary voltage V.sub.aux. As soon as the capacitor is charged to a given threshold, the LED string can be disconnected from the capacitor and the current through the LED string bypasses the auxiliary supply circuit. Thus, the current source provides a current through the LED string, which in turn may be selectively fed to the auxiliary power supply to provide auxiliary power back to the current source or to provide auxiliary power to other circuitry.

An optoelectronic circuit for receiving a variable voltage having alternating increasing and decreasing phases. The optoelectronic circuit includes an alternating arrangement of resistive elements and light-emitting diode sets mounted in series. Each set contains two terminals. Each resistive element is inserted between two consecutive sets. The optoelectronic circuit includes, for each set among a plurality of said sets, a depletion mode metal oxide semiconductor field effect transistor, the drain and the source of which are coupled with the terminals of said set and the gate of which is coupled with one of the terminals of the next set. An additional resistive element is, for at least some of the transistors, coupled between the drain or the source of the transistor and one of the terminals of the set.

A light-emitting element includes a light-emitting structure including a first conductive semiconductor layer, a second conductive semiconductor layer, and an active layer interposed between the first conductive semiconductor layer and the second conductive semiconductor layer; a first contact electrode and a second contact electrode located on the light-emitting structure, and respectively making ohmic contact with the first conductive semiconductor layer and the second conductive semiconductor layer; an insulation layer for covering a part of the first contact electrode and the second contact electrode so as to insulate the first contact electrode and the second contact electrode; a first electrode pad and a second electrode pad electrically connected to each of the first contact electrode and the second contact electrode; and a radiation pad formed on the insulation layer, and radiating heat generated from the light-emitting structure.

A display pixel suitable for being arranged on a carrier is provided. The display pixel includes a plurality of light-emitting diode chips. The light-emitting diode chips are disposed on and electrically connected to the carrier. Each of the light-emitting diode chips respectively serves as a sub-pixel and includes a semiconductor device layer, and the semiconductor device layer includes a display light-emitting mesa and at least one redundant light-emitting mesa. During a period of driving each of the light-emitting diode chips, one of the display light-emitting mesa and the at least one redundant light-emitting mesa in each of the light-emitting diode chips is capable of emitting light. A display panel including a plurality of the display pixels mentioned above is also provided.

In various embodiments, lighting systems include an electrically insulating carrier having a plurality of conductive elements disposed thereon and a light-emitting array. The light-emitting array is disposed over the carrier and includes a plurality of light-emitting diodes (LEDs) that each has at least two electrical contacts electrically connected to conductive elements by an electrical connection featuring solder.

An apparatus for positioning micro-devices on a destination substrate includes a first support to hold a destination substrate, a second support to provide or hold a transfer body having a surface to receive an adhesive layer, a light source to generate a light beam, a mirror configured to adjustably position the light beam on the adhesive layer on the transfer body, and a controller. The controller is configured to cause the light source to generate the light beam and adjust the mirror to position the light beam on the adhesive layer so as to selectively expose one or more portions of the adhesive layer to create one or more neutralized portions. The transfer body and the destination substrate are moved away from each other and one or more micro-devices corresponding to the one or more neutralized portions of the adhesive layer remain on the destination substrate.

Certain aspects of the technology disclosed herein integrate a camera with an electronic display. An electronic display includes several layers, such as a cover layer, a color filter layer, a display layer including light emitting diodes or organic light emitting diodes, a thin film transistor layer, etc. A processor initiates light emission from a plurality of display elements. The processor suspends the light emission from the plurality of display elements for a period of time imperceptible to a human observer. The processor initiates a camera to capture an image during the period of time the plurality of display elements are suspended. The processor can capture a plurality of images corresponding to a plurality of pixels and produce an image comprising depth information.

A display device with a semiconductor layer sequence includes an active region provided for generating radiation and a plurality of pixels. The display device also includes a carrier. The active region is arranged between a first semiconductor layer and a second semiconductor layer. The semiconductor layer sequence includes a recess, which extends from a major face of the semiconductor layer sequence facing the carrier through the active region into the first semiconductor layer and is provided for electrical contacting of the first semiconductor layer. The carrier includes a number of switches, which are each provided for controlling at least one pixel.

The invention disclosed a preparation method for a high-voltage LED device integrated with a pattern array, comprising the following process steps: providing a substrate, and forming a N-type GaN limiting layer, an epitaxial light-emitting layer and a P-type GaN limiting layer on the substrate in sequence; isolating the N-GaN limiting layer, the epitaxial light-emitting layer and the P-GaN limiting layer on the substrate into at least two or more independent pattern units by means of photo lithography and etching process, wherein each of the pattern unit is in a triangular shape, and very two adjacent pattern units are arranged in an opposing and crossed manner to form a quadrangle, and the quadrangles formed by a plurality of adjacent pattern units are distributed in array; and connecting each pattern unit with metal wires to form a series connection and/or a parallel connection, thereby forming a plurality of interconnected LED chips. For the purpose of improving the current distribution so as to increase the luminescent efficiency of the device, a current blocking layer is also arranged beneath the P-type metal contact of each unit in addition, an insulation material is also arranged to cover the surface of the chip so as to achieve the purposes of protecting the chip and increasing the light extraction efficiency of the chip.