To improve semiconductor-based systems for generating white light, a phosphor is integrated into a reflective material of an external structure. A disclosed exemplary system, for luminance or illumination applications, utilizes an energy source package, for emitting radiant energy of a first wavelength. The package typically contains an LED or other semiconductor device. A reflector outside the package has a reflective surface arranged to receive radiant energy from the energy source. At least some of the received radiant energy of the first wavelength excites one or more phosphors doped within the reflector to emit visible light, including visible light energy of at least one second wavelength different from the first wavelength. At least some of visible light emitted by the phosphor is reflected by the reflective surface of the reflector and directed to facilitate the particular humanly perceptible luminance or illumination application.
A light emitting diode includes a base board, at least one light emitting diodes fitted on an upper side of the base board, and a light shade made of either of glass and quartz, which is secured over said at least one light emitting diodes on the base board; the light shade has a fluorescent powder layer on a top thereof for changing color of light; the light shade has a reflecting layer on lateral wall portions thereof for reflecting light produced by the light emitting diodes such that light gathers at the top of the light shade to be brighter; furthermore, in manufacturing, the lateral wall portions of the light shade are soaked in and etched with hydrofluoric acid so as to have irregular depressions and lumps on the surfaces to enhance reflectivity of the reflecting layer.
A color-tunable illumination system for imaging illumination having a tuning means and at least two light sources of different colors. The illumination system comprises a reflector having a reflector contour, the light sources being accommodated in the vicinity of the reflector contour, and a compact diffusing medium accommodated at the focal point of the reflector. The light from the light sources is directed substantially onto the diffusing medium and then, from there, is diffused onto the reflector contour, electronic driving of the light sources making it possible to regulate the intensity of the light sources separately from one another, with the result that the light leaving the reflector can be color-tuned.
An optical manifold for efficiently combining a plurality of blue LED outputs to illuminate a phosphor for a single, substantially homogeneous output, in a small, cost-effective package. Embodiments are disclosed that use a single or multiple LEDs and a remote phosphor, and an intermediate wavelength-selective filter arranged so that backscattered photoluminescence is recycled to boost the luminance and flux of the output aperture. A further aperture mask is used to boost phosphor luminance with only modest loss of luminosity. Alternative non-recycling embodiments provide blue and yellow light in collimated beams, either separately or combined into white.
An optical manifold for efficiently combining a plurality of LED outputs into a single, substantially homogeneous output, in a small, cost-effective package. The optical manifolds can be used to combine multiple LEDs of the same color and provide a high intensity output aperture with very high uniformity and sharp borders, or they can be used to generate a multiwavelength output, such as red, green, and blue LEDs that are combined to generate white light. Embodiments are also disclosed that use a single or multiple LEDs and a remote phosphor and an intermediate wavelength-selective filter arranged so that backscattered photoluminescence is recycled to boost the luminance and flux of the output aperture. The optical manifolds are designed to alleviate substantial luminance inhomogeneities inherent to LEDs. The optical manifold utilizes principles of non-imaging optics to transform light and provide directed, substantially uniform light sources.
The invention discloses a high efficiency incandescent and Compact Fluorescent (CFL) bulb replacement LED lamp having a good color reproduction. The LED light bulb includes two groups of semiconductor light emitters and a luminescent material to emit four different spectrums of light. The two groups of semiconductor light emitters are enclosed around an interior wall of the light bulb housing, which has a plurality of fins at an exterior surface for effective heat dissipation. A high reflective member having a dome shape in the center is disposed under the two groups of semiconductor light emitters to redirect the emission and excitation lights from the two groups of semiconductor light emitters and recycle the backscattered light for multi-spectrum light mixing. The LED-light bulb further includes a single power line connecting to the two groups of semiconductor light emitters and a high efficiency electrical AC/DC conversion and control device. The light bulb has a diffuser dome for an output window and a conventional Edison-mount screw-type light bulb socket, a conventional fluorescent tube coupler arrangement or a conventional halogen MR-16 socket arrangement connecting to an AC power base. If a voltage is supplied to the AC/DC conversion and control device, a mixture light from the diffuser dome produces a warm white light with a color rendering index of at least 85 and a luminous efficacy of at least 80 lumens per watt.
