A red-luminescent long-afterglow phosphor, represented by Mg.sub.xZn.sub.yGe.sub.zO.sub.3: aMn.sup.2+, bEu.sup.3+, cR.sup.3+. The phosphor is a kind of oxide compound based white powder. The phosphor powder synthesis process is environmentally friendly, no sintering-assisted gas required and no harmful gas generated during or after sintering. The phosphor powder can be excited by UV and is chemically stable.

An LED pump light with multiple phosphors is described. LEDs emitting radiation at violet and/or ultraviolet wavelengths are used to pump phosphor materials that emit other colors. The LEDs operating in different wavelength ranges are arranged to reduce light re-absorption and improve light output efficiency.

An electrodeless discharge lamp with one or more stationary light emitting bulbs inside a common conductive shield to confine an electromagnetic excitation field provided by a plurality of sources. Each bulb can be excited by several electromagnetic radiation sources or by an individual electromagnetic radiation source. Tubular realization of the lamp, with two magnetron or transistor electromagnetic sources facing each other at the extremity of a tubular bulb, are particularly suitable for installation at the focal line of parabolic trough reflector. Some variants combine bulbs of different compositions, and excitation levels can be independently set to control the spectrum of emitted light.

A full spectrum light emitting device includes photoluminescence materials which generate light with a peak emission wavelength in a range 490 nm to 680 nm (green to red) and a broadband solid-state excitation source operable to generate broadband blue excitation light with a dominant wavelength in a range from 420 nm to 470 nm, where the broadband blue excitation light includes at least two different blue light emissions in a wavelength range 420 nm to 480 nm.

Provided are a material for wavelength conversion formed of a dipyrromethene boron complex compound having excellent solubility in a medium and exhibiting a sufficiently large molar absorption coefficient, a wavelength conversion member, a light emitting device, and a compound.

A material for wavelength conversion containing a compound represented by General Formula (1), a wavelength conversion member formed of the material for wavelength conversion, a light emitting device, and a compound.

##STR00001##

In the formula, R.sup.1 to R.sup.7 each represent a hydrogen atom or a substituent, and R.sup.8 and R.sup.9 each represent a specific substituent.

At least one of R.sup.1, . . . , or R.sup.9 has a partial structure represented by Formula (A).

##STR00002##

In the formula, R.sup.11 to R.sup.16 each represent a hydrogen atom or an alkyl group, and the symbol * represents a bonding site.

A two-wire load control device (such as, a dimmer switch) for controlling the amount of power delivered from an AC power source to an electrical load (such as, a high-efficiency lighting load) includes a thyristor coupled between the source and the load, a gate coupling circuit coupled between a first main load terminal and the gate of the thyristor, and a control circuit coupled to a control input of the gate coupling circuit. The control circuit generates a drive voltage for causing the gate coupling circuit to conduct a gate current to thus render the thyristor conductive at a firing time during a half cycle of the AC power source, and to allow the gate coupling circuit to conduct the gate current at any time from the firing time through approximately the remainder of the half cycle, where the gate coupling circuit conducts approximately no net average current to render and maintain the thyristor conductive.

Techniques for horticulture light are provided. A horticulture light can monitor at least one characteristic of a defined region in which at least one plant is planted in a horticulture environment in which horticulture light bulb is installed, determine at least one action for the horticulture light bulb to perform based on a state of the at least one characteristic and at least one objective of the installation of the horticulture light bulb in the horticulture environment, and execute the at least one action.

Digital dimmer for varying the luminous intensity of an electronic light source, including an operation interface module, arranged for receiving a user command, and a control and processing module, arranged for modulating each half cycle of alternating current on the basis of the user command. If the user command is to turn on the electronic light source at a dimming value lower than 25%, the control and processing module modulates the alternating current at a first dimming value equal or higher than 30% in a given number of half cycles of the alternating current, wherein the duration of the given number of half cycles is not perceptible by the user's eye. Then, the control and processing module modulates the alternating current at a second dimming value lower than 25% to ensure that the user sees only that the electronic light source lights up at the second dimming value.

A two-wire lighting control device, may include a controllably conductive device, a signal generation circuit, and a filter circuit. The controllably conductive device may apply an AC line voltage to a load, being conductive for a first duration of time and non-conductive for a second duration of time within a half-cycle of the AC line voltage. The signal generation circuit may generate a non-zero-magnitude signal. And, the filter circuit may receive a signal from the controllably conductive device during the first duration of time and the non-zero-magnitude signal from the signal generation circuit during the second duration of time. The non-zero-magnitude signal may, in effect, fill-in or complement the signal from the controllably conductive device, and any delay variation as a function of the firing angle of the controllably conductive device through the filter circuit may be mitigated by the presence of the non-zero-magnitude signal.

Provided is a method of producing semiconductor nanoparticles that exhibit a band-edge emission, and are superior in quantum yield. The method includes raising the temperature of a first mixture containing a silver (Ag) salt, a salt containing at least one of indium (In) and gallium (Ga), a solid compound that serves as a supply source of sulfur (S), and an organic solvent to a temperature in a range of from 125 □C to 175 □C, and heat-treating, subsequent to the raising of the temperature, the first mixture at a temperature in a range of from 125 □C to 175 □C for three seconds or more to obtain a solution containing semiconductor nanoparticles, and decreasing the temperature of the solution containing semiconductor nanoparticles. The solid compound that serves as a supply source of S contains thiourea.