A light emitting device includes a base having a light reflecting surface and having a first side on which the light reflecting surface is provided, light sources mounted on the first side, and a half mirror disposed opposite to the base to reflect a part of incident light and to transmit another part of the incident light. Each of the light sources includes a reflecting layer on an upper surface of each of the light sources. The half mirror has an oblique reflectance with respect to wavelengths of light emitted from the light sources in a case where the light travels obliquely toward the half mirror. The half mirror has a perpendicular reflectance with respect to the wavelengths in a case where the light travels perpendicularly toward the half mirror. The oblique reflectance is smaller than the perpendicular reflectance.

Lens assemblies for use in remote phosphor lighting systems, and methods of making and using them, are described. The lens assemblies typically include a lens member, a dichroic reflector attached to an outer surface of the lens member, and a phosphor layer attached to an inner surface of the lens member. The dichroic reflector reflects LED light originating from a given source point in a reference plane proximate the inner surface to a given image point in the reference plane. The phosphor layer may be patterned to cover one or more first portions of the inner surface and to expose one or more second portions, and/or the phosphor layer may be removably bonded to the inner surface. The lens assemblies can be readily combined with one or more short wavelength (e.g. blue) LEDs and other components to provide a remote phosphor lighting system.

The present invention provides a white light source comprising a light emitting diode having a light emission peak wavelength of 350 to 490 nm and a phosphor that emits visible light upon excitation by a light emitted from the light emitting diode; wherein, with respect to an arbitrary local maximum value of light-emission intensity between 350 and 780 nm of a light emission spectrum of the white light source, a ratio of a local minimum value of light-emission intensity that is closest on a long wavelength side to the local maximum value is such that, when the local maximum value is taken as 1, the local minimum value is 0.5 or more. It is preferable that, with respect to an arbitrary local maximum value of light-emission intensity between 350 and 780 nm of a light emission spectrum of the white light source, a ratio of a local minimum value of light-emission intensity that is closest on a long wavelength side to the local maximum value is such that, when the local maximum value is taken as 1, the local minimum value is 0.7 or more. According to the above structure, there can be provided a white light source capable of preventing a specified wavelength region from protruding in the light emission spectrum, and capable of visually perceiving the color tone of the irradiation object as the same state where the object is irradiated with sunlight.

Embodiments of a local optic using quantum dots are described. A local optic includes an optical source on a substrate, a housing, and a film that includes quantum dots. The housing is designed to fit around the optical source and has a cross-sectional area along a plane parallel to a surface of the substrate. The film is designed to sit on top of the housing and has a substantially similar cross-sectional area to the cross-sectional area of the housing.

A high-power, high-brightness lighting system for large venue lighting, which includes a laser diode as the excitation source and one or more phosphor materials placed at a remote distance from the laser source. The invention offers a lighting system with the advantages of high brightness, high efficiency, high luminous efficacy, long lifetimes, quick turn-on times, suitable color properties, environmental sustainability, and easy maintenance, which may allow for smart and flexible control over large area lighting systems with resulting savings in operating and maintenance costs.

The present invention provides a white light source comprising: a blue light emitting diode (blue LED) having a light emission peak wavelength in a range of 421 to 490 nm; and a phosphor layer including phosphor and resin, wherein the white light source satisfies a relational equation of 0.2[(P()V())/(P(max1)V(max1))(B)V())/(B(max2)V(max2))]+0.2, assuming that: a light emission spectrum of the white light source is P(); a light emission spectrum of black-body radiation having a same color temperature as that of the white light source is B(); a spectrum of a spectral luminous efficiency is V(); a wavelength at which P()V() becomes largest is max1; and a wavelength at which B()V() becomes largest is max2, and wherein an amount of chromaticity change on CIE chromaticity diagram from a time of initial lighting up of the white light source to a time after the white light source is continuously lighted up for 6000 hours is less than 0.010. According to the above white light source, there can be provided a white light source capable of reproducing the same light emission spectrum as that of natural light.

This lighting apparatus is provided with a blue LED s chip having a maximum peak at a wavelength of 420-480 nm and a fluorescent material-containing resin layer disposed on the front of the blue LED chip in the light emission direction. The fluorescent material-containing resin layer is obtained by mixing and dispersing a LuAg fluorescent material, which is represented by the formula Lu.sub.3Al.sub.5O.sub.12:Ce.sup.3+ and in which the Ce activation rate is 2 mol. % or lower relative to Lu, and a double fluoride fluorescent material represented by the formula A.sub.2(B.sub.1xMn.sub.x)F.sub.6 (in the formula, A is at least one type of element selected from among the group consisting of Li, Na, K and Cs, B is at least one type of element selected from among the group consisting of Si, Ti, Nb, Ge and Sn, and x is an integer that falls within the range 0.001x0.1) in a resin. The present invention is capable of achieving a higher sense of brightness, high visibility and a sense of brightness across a wide range under scotopic conditions or mesopic conditions with an emitted light color close to black body radiation.