Solid state illumination system containing a light emitting diode, a light scattering material and a luminescent material

A light emitting device, comprising:

• a radiation source;
• a luminescent material;
• and
• a radiation scattering material located between the radiation source and the luminescent material;
• wherein:
• the radiation scattering material comprises radiation scattering particles in a packed layer located separately from the luminescent material;
• the radiation source comprises a light emitting diode or a laser diode emitting radiation having a first peak emission wavelength;
• and
• the luminescent material comprises an organic dye which emits radiation having a second peak wavelength in response to incident radiation source radiation.

A light emitting device, comprising:

• a radiation source;
• a luminescent material;
• a radiation scattering material located between the radiation source and the luminescent material;
• and
• a package supporting the radiation source;
• wherein:
• the radiation scattering material comprises radiation scattering particles located separately from the luminescent material;
• the radiation source comprises a light emitting diode emitting radiation having a first peak emission wavelength;
• the luminescent material comprises a phosphor which emits radiation having a second peak wavelength in response to incident radiation source radiation;
• the radiation scattering material comprises the radiation scattering particles located in a carrier medium comprising a transmissive body and a light or UV radiation scattering particle layer located on sidewalls of a reflector cup portion of the package containing the light emitting diode;
• and
• the radiation scattering particles in the carrier medium are located above the light emitting diode and the luminescent material is located above the radiation scattering particles in the carrier medium.

A light emitting device, comprising:

• a radiation source;
• a luminescent material;
• and
• a radiation scattering material located between the radiation source and the luminescent material;
• wherein:
• the radiation scattering material comprises radiation scattering particles located separately from the luminescent material;
• the radiation source comprises a light emitting diode or a laser diode emitting radiation having a first peak emission wavelength;
• the luminescent material comprises a phosphor which emits radiation having a second peak wavelength in response to incident radiation source radiation;
• and
• the radiation scattering particles are located in a carrier medium comprising a transmissive body and the radiation scattering particles comprise at least two layers of TiO2 particles in about a 1 micron to about a 2 micron thick silica layer arranged to achieve photonic crystal effects.

A white light emitting device, comprising:

• a package containing a reflector cup;
• a light emitting diode in the reflector cup;
• radiation scattering particles in a packed layer over the light emitting diode;
• and
• a phosphor or an organic dye which emits radiation having a second peak wavelength in response to incident light emitting diode radiation having a first peak wavelength, such that the device output appears white to an observer;
• wherein the phosphor or organic dye is located over and separately from the radiation scattering particles located in the packed layer and the phosphor or organic dye comprises a layer which does not contain radiation scattering particles.

A white light emitting device, comprising:

• a package containing a reflector cup;
• a light emitting diode in the reflector cup;
• radiation scattering particles in a carrier medium over the light emitting diode;
• and
• a phosphor which emits radiation having a second peak wavelength in response to incident light emitting diode radiation having a first peak wavelength, such that the device output appears white to an observer;
• wherein:
• the phosphor is located over and separately from the radiation scattering particles located in the carrier medium;
• the light emitting diode comprises a blue or an ultraviolet light emitting diode;
• the radiation scattering particles comprise light or UV radiation scattering particles in the carrier medium;
• the phosphor comprises a yellow or white light emitting phosphor layer or a dispersion of a phosphor in an epoxy or silicone;
• the radiation scattering particles are selected from a group consisting of TiO2, BaTiO3, Al2O3, SiO2, CaCO3, BaSO4 and diamond particles having a mean diameter of 50 to 500 nm;
• and
• the carrier medium is selected from glass, epoxy, silicone and urea resin.

A white light emitting device, comprising:

• a package containing a reflector cup;
• a light emitting diode in the reflector cup;
• radiation scattering particles in a carrier medium over the light emitting diode;
• and
• a phosphor which emits radiation having a second peak wavelength in response to incident light emitting diode radiation having a first peak wavelength, such that the device output appears white to an observer;
• wherein:
• the phosphor is located over and separately from the radiation scattering particles located in the carrier medium;
• the light emitting diode comprises a blue or an ultraviolet light emitting diode;
• the radiation scattering particles comprise light or UV radiation scattering particles in the carrier medium;
• the phosphor comprises a yellow or white light emitting phosphor layer or a dispersion of a phosphor in an epoxy or silicone;
• a mean diameter of the radiation scattering particles is between λ/3 and λ/2, where λ is the peak emission wavelength of the radiation source;
• and
• the radiation scattering particles scatter at least 50% more radiation source radiation than luminescent material radiation.

A method of generating white light from a light emitting device, comprising a light emitting diode, a phosphor luminescent material and a radiation scattering material located between the light emitting diode and the luminescent material, wherein the radiation scattering material comprises radiation scattering particles located separately from the luminescent material, and a mean diameter of the radiation scattering particles is between λ/3 and λ/2, where k is a first peak emission wavelength of the radiation source;

• the method comprising:
• supplying power to the light emitting diode;
• generating a directional radiation comprising blue light or ultraviolet radiation having the first peak emission wavelength;
• passing the directional radiation through the radiation scattering material to diffuse the directional radiation in a plurality of directions;
• providing the diffuse radiation comprising blue light or ultraviolet radiation onto the luminescent material;
• and
• generating white light by emitting radiation having a second peak wavelength from the luminescent material.

A light emitting device, comprising:

• a radiation source;
• a luminescent material layer which does not substantially exhibit Mie scattering;
• and
• a radiation scattering phosphor layer, which exhibits Mie scattering of the radiation source radiation, located between the radiation source and the luminescent material.