An improved system and method for reading an upconversion response from nanoparticle inks is provided. A is adapted to direct a near-infrared excitation wavelength at a readable indicia, resulting in a near-infrared emission wavelength created by the upconverting nanoparticle inks. A short pass filter may filter the near-infrared excitation wavelength. A camera is in operable communication with the short pass filter and receives the near-infrared emission wavelength of the readable indicia. The system may further include an integrated circuit adapted to receive the near-infrared emission wavelength from the camera and generate a corresponding signal. A readable application may be in operable communication with the integrated circuit. The readable application receives the corresponding signal, manipulates the signal, decodes the signal into an output, and displays and/or stores the output.

A phosphor is specified. The phosphor has the general molecular formula:
(MA).sub.a(MB).sub.b(MC).sub.c(MD).sub.d(TA).sub.e(TB).sub.f(TC).sub.g(TD).sub.h(TE).sub.i(TF).sub.j(XA).sub.k(XB).sub.l(XC).sub.m(XD).sub.n:E.
In this case, MA is selected from a group of monovalent metals, MB is selected from a group of divalent metals, MC is selected from a group of trivalent metals, MD is selected from a group of tetravalent metals, TA is selected from a group of monovalent metals, TB is selected from a group of divalent metals, TC is selected from a group of trivalent metals, TD is selected from a group of tetravalent metals, TE is selected from a group of pentavalent elements, TF is selected from a group of hexavalent elements, XA is selected from a group of elements which comprises halogens, XB is selected from a group of elements which comprises O, S and combinations thereof, -E=Eu, Ce, Yb and/or Mn, XC=N and XD=C. The following furthermore hold true: a+b+c+d=t; e+f+g+h+i+j=u; k+l+m+n=v; a+2b+3c+4d+e+2f+3g+4h+5i+6j−k−2l−3m−4n=w; 0.8≤t≤1; 3.5≤u≤4; 3.5≤v≤4; (−0.2)≤w≤0.2 and 0≤m<0.875 v and/or v≥1>0.125 v.

A wavelength converter 100 includes: a first phosphor 1 composed of an inorganic phosphor activated by Ce.sup.3+; and a second phosphor 2 composed of an inorganic phosphor activated by Ce.sup.3+ and different from the first phosphor. At least one of the first phosphor and the second phosphor is particulate. The first phosphor and the second phosphor are bonded to each other by at least one of a chemical reaction in a contact portion between the compound that constitutes the first phosphor and a compound that constitutes the second phosphor and of adhesion between the compound that constitutes the first phosphor and the compound that constitutes the second phosphor.

A light emitting assembly comprising at least one of each of a solid state device and a thermal radiation source, couplable with a power supply constructed and arranged to power the solid state device and the thermal radiation source, to emit from the solid state device a first, relatively shorter wavelength radiation, and to emit from the thermal radiation source non-visible infrared radiation, and a down-converting luminophoric medium arranged in receiving relationship to said first, relatively shorter wavelength radiation, and the infrared radiation, and which in exposure to said first, relatively shorter wavelength radiation, and infrared radiation, is excited to responsively emit second, relatively longer wavelength radiation. In a specific embodiment, monochromatic blue light output from a light-emitting diode is down-converted to white light by packaging the diode and the thermal radiation device with fluorescent or phosphorescent organic and/or inorganic fluorescers and phosphors in an enclosure.

A method includes mounting a ceramic phosphor on an acrylic-free and metal-containing catalyst-free tacky layer of a dicing tape, dicing the ceramic phosphor from the dicing tape into ceramic phosphor plates, removing the ceramic phosphor plates from the dicing tape, and attaching the ceramic phosphor plates on light-emitting device (LED) dies.

A method includes mounting a ceramic phosphor on an acrylic-free and metal-containing catalyst-free tacky layer of a dicing tape, dicing the ceramic phosphor from the dicing tape into ceramic phosphor plates, removing the ceramic phosphor plates from the dicing tape, and attaching the ceramic phosphor plates on light-emitting device (LED) dies.

According to one embodiment, a white light source includes a combination of a light emitting diode and phosphors. One of the phosphors is at least a cerium activated yttrium aluminum garnet-based phosphor. There is no light emission spectrum peak at which a ratio of a largest maximum value to a minimum value is greater than 1.9. The largest maximum value is largest among at least one maximum value present in a wavelength range of 400 nm to 500 nm in a light emission spectrum of white light emitted from the white light source. The minimum value is adjacent to the largest maximum value in a longer wavelength side of the light emission spectrum.

A light emitting device including a housing including walls defining a cavity having one side thereof opened, a light emitter to emit light having a peak wavelength in a blue wavelength band and including first and second light emitting chips, a reflective region in the housing to reflect light, and a wavelength conversion layer disposed on the light emitter and including a first wavelength converter and a second wavelength converter to emit light having different peak wavelengths from each other, in which the first wavelength converter has a first excitation peak wavelength and the second wavelength converter has a second excitation peak wavelength, and the second wavelength converter includes a fluoride-based red phosphor represented by A.sub.2MF.sub.6:Mn.sup.4+, where A is one of Li, Na, K, Ba, Rb, Cs, Mg, Ca, Se, and Zn, and M is one of Ti, Si, Zr, Sn, and Ge.

Provided is a method for producing a β-sialon fluorescent material, comprising preparing a composition containing a silicon nitride that contains aluminium, oxygen, and europium; heat-treating the composition at a temperature in a range of 1300° C. or more and 1600° C. or less to obtain a heat-treated product; subjecting the heat-treated product to a temperature-decrease of from the heat treatment temperature to 1000° C. as a first temperature-decrease step; and subjecting the heat-treated product to a temperature-decrease of from 1000° C. to 400° C. as a second temperature-decrease step. The first temperature-decrease step has a temperature-decrease rate in a range of 1.5° C./min or more and 200° C./min or less, and the second temperature-decrease step has a temperature-decrease rate in a range of 1° C./min or more and 200° C./min or less.

One aspect of the disclosure provides an optical wavelength conversion member including a polycrystalline ceramic sintered body containing, as main components, Al.sub.2O.sub.3 crystal grains and crystal grains represented by formula (Y,A).sub.3B.sub.5O.sub.12:Ce. In the optical wavelength conversion member, a (Y,A).sub.3B.sub.5O.sub.12:Ce crystal grain has a region wherein the A concentration of a peripheral portion of the (Y,A).sub.3B.sub.5O.sub.12:Ce crystal grain is higher than that of an interior portion of the (Y,A).sub.3B.sub.5O.sub.12:Ce crystal grain. Thus, the optical wavelength conversion member exhibits high fluorescence intensity (i.e., high emission intensity) and high heat resistance (i.e., low likelihood of temperature quenching). The optical wavelength conversion member has a structure wherein the element A concentration of a peripheral portion of a (Y,A).sub.3B.sub.5O.sub.12:Ce crystal grain differs from that in an interior portion of the crystal grain. This structure can achieve a ceramic fluorescent body exhibiting superior fluorescent characteristics and superior thermal characteristics with varied colors of emitted light.