Abstract:
A display backlight, comprises: an excitation source, LED (146), for generating blue excitation light (148) with a peak emission wavelength in a wavelength range 445 nm to 465 nm; and a photoluminescence wavelength conversion layer (152). The photoluminescence wavelength conversion layer (152) comprises a mixture of a green-emitting photoluminescence material with a peak emission in a wavelength range 530 nm to 545 nm, a red-emitting photoluminescence material with a peak emission in a wavelength range 600 nm to 650 nm and particles of light scattering material.
Abstract:
A color wheel comprises: a rotatable disc having a light reflective face and a region of photolummescence material deposited on the light reflective face. The region of photolummescence material comprises a substantially uniform thickness layer of a mixture of particles of the photolummescence material that is deposited on the light reflective face of the disc by screen printing. The photolummescence materials can comprise blue light or UV excitable photolummescence materials such as phosphor materials or quantum dots. Color modulated light sources and a method of manufacturing a color wheel are also disclosed.
Abstract:
A photoluminescent composition ("phosphor ink") comprises a suspension of particles of at least one blue light (380nm to 480nm) excitable phosphor material in a light transmissive liquid binder in which the weight loading of at least one phosphor material to binder material is in a range 40% to 75%. The binder can be U.V. curable, thermally curable, solvent based or a combination thereof and comprise a polymer resin; a monomer resin, an acrylic, a silicone or a fluorinated polymer. The composition can further comprise particles of a light reflective material suspended in the liquid binder. Photoluminescence wavelength conversion components; solid-state light emitting devices; light emitting signage surfaces and light emitting signage utilizing the composition are disclosed.
Abstract:
A full spectrum white light emitting device comprises photoluminescence materials for generating light with a peak emission wavelength from 490 nm to 680 nm; and a broadband solid-state excitation source for generating broadband excitation light with a dominant wavelength from 420 nm to 480 nm. The device generates white light having a spectrum whose intensity decreases from its maximum value in the orange to red wavelength region of the spectrum to about 50% of said maximum value at a wavelength from 645 nm to 695 nm, and over a wavelength range from about 430 nm to about 520 nm, a maximum percentage intensity deviation of said white light from the intensity of light of a black-body curve or CIE Standard Illuminant D is less than 60%.
Abstract:
A full spectrum light emitting device (310a) comprises photoluminescence materials (e.g. in encapsulant 366) which generates 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, wherein the broadband blue excitation light comprises at least two different blue light emissions (from LED chips 330 and 332 respectively) in a wavelength range 420 nm to 480 nm.
Abstract:
A display backlight, comprising: an excitation source (42) for generating blue excitation light with a dominant emission wavelength in a range 445 nm to 465 nm; a red photoluminescence material with a peak emission wavelength in a range 610 nm to 650 nm; and a europium activated sulfide phosphor having a peak emission wavelength in a range 525 nm to 545 nm.
Abstract:
A wavelength conversion component for a light emitting device comprises at least one photoluminescence material; and a light scattering material. The light scattering material has an average particle size that is selected such that the light scattering material will scatter excitation light from a radiation source relatively more than the light scattering material will scatter light generated by the at least one photoluminescence material. Use of a light scattering material can reduce usage of the photoluminescence material and can improve an OFF state appearance of the component.
Abstract:
A solid-state light emitting device comprises a solid-state light emitter (LED) operable to generate excitation light and a wavelength conversion component including a mixture of particles of a photoluminescence material and particles of a light reflective material. The phosphor absorbs at least a portion of the excitation light and emits light of a different color. The emission product of the device comprises the combined light generated by the LED and the phosphor. The wavelength conversion component can be light transmissive and comprise a light transmissive substrate on which the mixture of phosphor and reflective materials is provided as a layer or homogeneously distributed throughout the volume of the substrate. Alternatively the wavelength conversion component can be light reflective with the mixture of phosphor and light reflective materials being provided as a layer on the light reflective surface.
Abstract:
Embodiments of the present invention are directed to nitride-based, red-emitting phosphors in red, green, and blue (RGB) lighting systems, which in turn may be used in backlighting displays and warm white-light applications. In particular embodiments, the red-emitting phosphor is based on CaAlSiN 3 type compounds activated with divalent europium. In one embodiment, the nitride-based, red emitting compound contains a solid solution of calcium and strontium compounds (Ca,Sr)AlSiN 3 :Eu 2+ , wherein the impurity oxygen content is less than about 2 percent by weight. In another embodiment, the (Ca,Sr)AlSiN 3 :Eu 2+ compounds further contains a halogen in an amount ranging from about zero to about 2 atomic percent, where the halogen may be fluorine (F), chlorine (Cl), or any combination thereof. In one embodiment at least half of the halogen is distributed on 2-fold coordinated nitrogen (N2) sites relative to 3-fold coordinated nitrogen (N3) sites.
Abstract:
A nitride-based deep red phosphor having at least one of the following features: 1) an oxygen content less than about 2 percent by weight, and 2) a halogen content. Such phosphors are useful in the white light illumination industry, which utilizes the so-called "white LED." The selection and use of a rare earth halide as a raw material source of not only the activator for the phosphor, but also the halogen, is a feature of the present embodiments. The phosphors have the general formula MaMbBc(N,D):Eu2+, where Ma is a divalent alkaline earth metal such as Mg, Ca, Sr, Ba; Mb is a trivalent metal such as Al, Ga, Bi, Y, La, and Sm; and Mc is a tetravalent element such as Si, Ge, P, and B; N is nitrogen, and D is a halogen such as F, Cl, or Br. An exemplary compound is CaAlSi(N1-xFx): Eu2+.