Abstract: An LED die, a wafer of LED dies, and methods of manufacture are described. The LED die includes a semiconductor stack configured to emit a pump light when energized and a wavelength converter over the semiconductor stack. The wavelength converter converts some of the pump light to a converted light having a differing color. A spatially inhomogeneous dichroic filter on the wavelength converter, which at least one of: increases reflection of the pump light in special regions of peak luminance, increases reflection of the converted light in spatial regions of low luminance, increases transmission in at least a portion of the converted light in spatial regions of peak luminance, or increases transmission of the pump light in spatial regions of low luminance.

Abstract: This specification discloses a converter element and light emitting devices including the converter element. The converter element is monolithic with at least two layers, where one layer is more porous than the other layer. The converter element may be integrated with a reflector layer, such as by metallization. The layer of the converter structure that is denser and having a smoother surface may be the one that is metallized, while the more porous layer is closer to the laser. The porosity enhances light extraction while the smoother surface decreases a loss of reflectivity at the reflector-phosphor interface. The converter element may be used in a laser based light emitting device.

Abstract: A light-emitting diode (LED) die can include a p-n junction between a p-doped semiconductor material and an n-doped semiconductor material. The LED die can include vias that can electrically power the p-n junction. The vias can optionally be electrically connected in parallel to one another. A controller can supply current to the vias to electrically power the LED die. The vias can be distributed with a density that peaks at or near a center of the LED die and decreases with increasing distances away from the peak of the density, such that when the vias are electrically powered, the LED die emits light with a surface luminance that peaks at or near the center of the LED die and decreases with increasing distances away from the peak of the surface luminance.

Abstract: This specification discloses LEDs and LED arrays configured such that an electric field may be applied during operation of the device to drive charge carriers (electrons or holes) away from perimeter semiconductor surfaces of the LEDs, thereby reducing non-radiative recombination near those perimeter surfaces. These LEDs and LED arrays comprise (e.g., metal) field plates, arranged around the perimeter surfaces of the LEDs, by which the electric field may be applied. In some variations, the bias voltage applied to the field plates to produce the electric fields may be separately controlled for some, or each, LED in an array. In other variations the bias applied to the field plates is the same for each LED in an array.

Abstract: An n-doped semiconductor layer spans multiple LEDs of an array, in some cases the entire array. Corresponding p-contacts are localized on the p-doped semiconductor layer of each LED to only a central region of that LED and are electrically isolated from the p-contacts of adjacent LEDs. Corresponding n-contacts (i) are localized to only peripheral regions of the corresponding LEDs, (ii) extend through the p-doped layers and the active regions of adjacent LEDs to make contact with the continuous n-doped layer, and (iii) are electrically isolated from those p-doped layers and active regions. In some cases the nonzero combined thickness of the n-doped layer, p-doped layer, and the active region can be less than 5 ?m.

Abstract: Methods and devices including a die with a segmented transparent conductive oxide structure and/or a distributed bragg reflector (DBR) may improve optical efficiency and/or reflectivity of the system. The process of fabricating such a die has an improved workflow that may decrease the number of steps and/or masks used, such as by simultaneously depositing and/or patterning one or more structures in the die which may conventionally require more than one step. In this way, the luminous flux of the completed die is improved while the cost of production is decreased.

Abstract: Methods and devices including a die with a plurality of metal reflectors and/or a distributed bragg reflector (DBR) may improve optical efficiency and/or reflectivity of the system. The metal reflectors may be highly reflective and cover most of the die area including at least most of the n-contact areas. The DBR may also cover most of the die areas. Reflectivity may be improved as a result of one or both of these elements. Additionally, a transparent conductive oxide layer may cover the n-contact areas to improve current spreading.

Abstract: A semiconductor LED includes p-doped, n-doped, and active layers, and has anode and cathode electrical contacts. The active layer extend to the side surfaces of the LED; the anode contact is on a central area of the p-doped layer and leaves peripheral regions without direct electrical coupling to the anode contact, reducing non-radiative recombination at the side surfaces. The LED can include a front reflector with a central opening aligned with the anode contact. The LED can include front, side, and back reflectors to form an optical cavity enclosing the n- and p-doped semiconductor layers and the active layer. At least a portion of the central opening is positioned opposite at least a portion of the central area of the anode contact surface.

Abstract: A light-emitting device includes a semiconductor diode structure with one or more light-emitting active layers, an anti-reflection coating on its front surface, and a redirection layer on its back surface. Active-layer output light propagates within the diode structure. The anti-reflection coating on the front surface increases transmission of active-layer output light incident below the critical angle ?c. Active-layer output light incident on the redirection layer at an incidence angle greater than ?c is redirected to propagate toward the front surface at an incidence angle that is less than ?c. Device output light is transmitted by the front surface to propagate in an ambient medium, and includes first and second portions of the active-layer output light incident on the front surface at an incidence angle less than ?c, the first portion without redirection by the redirection layer and the second portion with redirection by the redirection layer.

Abstract: A light-emitting device includes: a semiconductor diode structure, a reflector, a wavelength-converting layer, and an intermediate spacer between the diode structure and the wavelength-converting layer. The diode structure emits diode output light at a vacuum wavelength ?0 to propagate within the diode structure. The reflector is on the back diode structure and internally reflects diode internally incident output light. The wavelength-converting layer is positioned with its back surface facing and spaced-apart from a front surface of the diode structure, and absorbs diode output light at ?0 and emits down-converted light at a vacuum wavelength ?1>?0, which exits the wavelength-converting layer through its front surface.

Abstract: A micro light emitting diode (LED) die can include a matrix of micro LEDs with a variety of forward voltages. A method of reducing a number of undriven or under driven uLEDs can include providing, by a power supply, an alternating current voltage (VLED) with a minimum voltage (VMIN) and a maximum voltage (VMAX), VMIN being sufficient to drive a plurality of micro light emitting diodes (uLEDs) of a uLED die using a plurality of uLED drivers, identifying, by a controller coupled to the uLED drivers, a uLED of the plurality of uLEDs with a forward voltage (Vf) greater than VMIN, and altering, by the controller, a time of a rising edge of a pulse width modulation (PWM)-on time of the uLED such that Vf of the uLED is less than VLED for the PWM-on time.

Abstract: Optical filters are used to compensate for changes in LED and pcLED performance resulting from technological advances in device design or manufacturing, with for example the filtered optical output from later generation devices matching or substantially matching the optical performance of earlier generation legacy devices. This can allow the advanced generation devices to be substituted in applications previously supported by the legacy devices, even if the optical performance of the unfiltered advanced generation devices does not satisfy the optical performance specifications required by the application. Somewhat paradoxically, the advantages of using the filters in combination with the advanced generation devices may arise from the filters making the optical performance of the devices worse according to one or more figures of merit.

Abstract: Optical filters are used to compensate for changes in LED and pcLED performance resulting from technological advances in device design or manufacturing, with for example the filtered optical output from later generation devices matching or substantially matching the optical performance of earlier generation legacy devices. This can allow the advanced generation devices to be substituted in applications previously supported by the legacy devices, even if the optical performance of the unfiltered advanced generation devices does not satisfy the optical performance specifications required by the application. Somewhat paradoxically, the advantages of using the filters in combination with the advanced generation devices may arise from the filters making the optical performance of the devices worse according to one or more figures of merit.

Abstract: A light-emitting device includes: a semiconductor diode structure, a reflector, a wavelength-converting layer, and an intermediate spacer between the diode structure and the wavelength-converting layer. The diode structure emits diode output light at a vacuum wavelength ?0 to propagate within the diode structure. The reflector is on the back diode structure and internally reflects diode internally incident output light. The wavelength-converting layer is positioned with its back surface facing and spaced-apart from a front surface of the diode structure, and absorbs diode output light at ?0 and emits down-converted light at a vacuum wavelength ?1>?0, which exits the wavelength-converting layer through its front surface.

Abstract: A control system for an LED array relies on defining a first and a second group of separately addressed LED pixels, with the first group including pixels with an average current no less than the current at a Q point and a second group including pixels with an average current less than the current at a Q point. An amplitude signal provided to the first group of separately addressed LED pixels is selectively modulated, while providing a DC mode 100% duty cycle. An amplitude signal provided to the second group of separately addressed LED pixels is fixed, and a modulated duty cycle is provided.

Abstract: A light-emitting array includes a semiconductor LED structure, multiple transparent dielectric bodies, a set of multiple, independent first electrical contacts, and a set of second electrical contacts. The LED structure extends contiguously over the array. The second electrical contacts are in electrical contact with the second semiconductor layer. Each dielectric body protrudes away from the first semiconductor layer and has on its surface an electrically conductive layer in electrical contact with the first semiconductor layer, forming a portion of a corresponding one of the first electrical contacts. Each dielectric body and corresponding first electrical contact define a corresponding discrete, circumscribed pixel region within the contiguous area of the array, each pixel region separate from the others.

Abstract: A nano-structure layer is disclosed. The nano-structure layer includes an array of nano-structure material configured to receive a first light beam at a first angle of incidence and to emit the first light beam at a second angle greater than the first angle, the nano-structure material each having a largest dimension of less than 1000 nm.

Abstract: A control system for an LED array relies on defining a first and a second group of separately addressed LED pixels, with the first group including pixels with an average current no less than the current at a Q point and a second group including pixels with an average current less than the current at a Q point. An amplitude signal provided to the first group of separately addressed LED pixels is selectively modulated, while providing a DC mode 100% duty cycle. An amplitude signal provided to the second group of separately addressed LED pixels is fixed, and a modulated duty cycle is provided.

Abstract: A micro light emitting diode (LED) die can include a matrix of micro LEDs with a variety of forward voltages. A method of reducing a number of undriven or under driven uLEDs can include providing, by a power supply, an alternating current voltage (VLED) with a minimum voltage (VMIN) and a maximum voltage (VMAX), VMIN being sufficient to drive a plurality of micro light emitting diodes (uLEDs) of a uLED die using a plurality of uLED drivers, identifying, by a controller coupled to the uLED drivers, a uLED of the plurality of uLEDs with a forward voltage (Vf) greater than VMIN, and altering, by the controller, a time of a rising edge of a pulse width modulation (PWM)-on time of the uLED such that Vf of the uLED is less than VLED for the PWM-on time.

Abstract: A light-emitting device includes a semiconductor diode structure with one or more light-emitting active layers, an anti-reflection coating on its front surface, and a redirection layer on its back surface. Active-layer output light propagates within the diode structure. The anti-reflection coating on the front surface increases transmission of active-layer output light incident below the critical angle ?c. Active-layer output light incident on the redirection layer at an incidence angle greater than ?c is redirected to propagate toward the front surface at an incidence angle that is less than ?c. Device output light is transmitted by the front surface to propagate in an ambient medium, and includes first and second portions of the active-layer output light incident on the front surface at an incidence angle less than ?c, the first portion without redirection by the redirection layer and the second portion with redirection by the redirection layer.