UV reflectors and UV-based light sources having reduced UV radiation leakage incorporating the same

A UV reflector comprising a plurality of layers of materials having at least alternating first and second refractive indices;

• wherein said first refractive index is smaller than said second refractive index;
• a first layer of said plurality of layers comprises a material having said first refractive index;
• said reflector further comprises an additional layer of a material having a third refractive index less than said first refractive index, said additional layer being attached to said first layer to receive an incident light having wavelengths in a UV-to-visible spectrum;
• and a plurality of protrusions included on a surface of said additional layer on which said incident light impinges.

A light source based on at least one UV LED, said light source comprising:

• a LED emitting UV radiation;
• a shaped structure that comprises a substantially transparent molding or casting material, said shaped structure covering said LED;
• particles of at least one phosphor that is excitable by said UV radiation, said phosphor disposed to receive said UV radiation and to convert said UV radiation to visible light;
• and
• particles of at least one UV-radiation scattering material disposed among said particles of said phosphor;
• wherein said particles of said phosphor and said particles of said scattering material are dispersed in at least a portion of said molding or casting material, which transmits greater than 80% of incident light having a wavelength of 555 nm at an incident angle of less than 10 degrees, and said particles are disposed in a vicinity of said LED.

A light source based on at least one UV LED, said light source comprising:

• a LED emitting UV radiation;
• a shaped structure that comprises a substantially transparent molding or casting material, said shaped structure covering said LED;
• particles of at least one phosphor that is excitable by said UV radiation, said phosphor disposed to receive said UV radiation and to convert said UV radiation to visible light;
• and
• particles of at least one UV-radiation scattering material disposed among said particles of said phosphor;
• wherein said particles of said phosphor and said particles of said scattering material are dispersed in at least a portion of said molding or casting material;
• said particles are disposed in a vicinity of said LED;
• said UV-radiation scattering material has a refractive index less than the refractive index of said molding or casting material, said refractive indices being measured for light having wavelength of 555 nm;
• and said UV-radiation scattering material is selected from the group consisting of lithium fluoride, magnesium fluoride, potassium fluoride, sodium fluoride, and mixtures thereof.

A light source based on at least one UV LED, said light source comprising:

• a LED emitting UV radiation;
• a shaped structure that comprises a substantially transparent molding or casting material, said shaped structure covering said LED;
• particles of at least one phosphor that is excitable by said UV radiation, said phosphor disposed to receive said UV radiation and to convert said UV radiation to visible light;
• and
• particles of at least one UV-radiation scattering material disposed among said particles of said phosphor;
• wherein said particles of said phosphor and said particles of said scattering material are dispersed in at least a portion of said molding or casting material;
• said particles are disposed in a vicinity of said LED;
• said UV-radiation scattering material has a refractive index different from the refractive index of said molding or casting material, said refractive indices being measured for light having wavelength of 555 nm;
• and said UV-radiation scattering material is a particulate dielectric material of which greater than 95% of the particle population has a particle diameterless than about half of a maximum wavelength of UV radiation in said substantially transparent molding or casting material and which has a mean particle diameter less than about one-tenth of said wavelength.

A light source based on at least one UV LED, said light source comprising:

• a LED emitting UV radiation;
• a shaped structure that comprises a first substantially transparent molding or casting material, said shaped structure covering said LED;
• particles of at least one phosphor that is excitable by said UV radiation, said phosphor disposed to receive said UV radiation and to convert said UV radiation to visible light;
• particles of at least one first UV-radiation scattering material disposed among said particles of said phosphor;
• and
• a layer that comprises particles of a second UV-radiation scattering material dispersed in a second substantially transparent molding or casting material, said layer being disposed on said shaped structure in a direction of a viewer;
• wherein said particles of said phosphor and said particles of said first scattering material are dispersed in at least a portion of said first molding or casting material;
• said particles are disposed in a vicinity of said LED;
• said first and second UV-radiation scattering materials have refractive indices different from the refractive indices of said first and second molding or casting materials, said refractive indices being measured for light having wavelength of 555 nm.

A light source based on at least one UV LED, said light source comprising:

• a LED emitting UV radiation;
• a shaped structure that comprises a substantially transparent molding or casting material, said shaped structure covering said LED;
• particles of at least one phosphor that is excitable by said UV radiation, said phosphor disposed to receive said UV radiation and to convert said UV radiation to visible light;
• and
• a plurality of air bubbles having nanometer sizes, said air bubbles being formed among said particles of said phosphor in said substantially transparent molding or casting material;
• wherein said particles of said phosphor and said air bubbles are dispersed in at least a portion of said molding or casting material and are disposed in a vicinity of said LED, and said molding or casting material transmits greater than 80% of incident light having a wavelength of 555 nm at an incident angle of less than 10 degrees.

A light source based on at least one UV LED, said light source comprising:

• a LED emitting UV radiation;
• a shaped structure that comprises a substantially transparent molding or casting material, said shaped structure covering said LED;
• particles of at least one phosphor that is excitable by said UV radiation, said phosphor disposed in a vicinity of said LED to receive said UV radiation and to convert said UV radiation to visible light, said particles of said phosphor dispersed in a portion of said molding or casting material;
• and
• a UV reflector comprising a plurality of layers of materials having at least alternating first and second refractive indices, said first refractive index being smaller than said second refractive index, said UV reflector being disposed on said shaped structure in a direction of a viewer;
• wherein a first layer of said plurality of layers is disposed adjacent to said shaped structure, and said plurality of layers consists of an odd number of layers.

A light source based on at least one UV LED, said light source comprising:

• a LED emitting UV radiation;
• a shaped structure that comprises a substantially transparent molding or casting material, said shaped structure covering said LED;
• particles of at least one phosphor that is excitable by said UV radiation, said phosphor disposed in a vicinity of said LED to receive said UV radiation and to convert said UV radiation to visible light, said particles of said phosphor dispersed in a portion of said molding or casting material;
• and
• a UV reflector comprising a plurality of layers of materials having at least alternating first and second refractive indices, said first refractive index being smaller than said second refractive index, said UV reflector being disposed on said shaped structure in a direction of a viewer, wherein a first layer of said plurality of layers is disposed adjacent to said shaped structure;
• wherein said first layer of said plurality of layers comprises a material having said first refractive index;
• said first layer receives an incident light traversing said shaped structure;
• and each of said plurality of layers has a physical thickness in a range from about 540 k/(4 n) nm to about 580 k/(4 n) nm, wherein k is a positive integer selected from the group consisting of 1 and positive even integer numbers and wherein n is a refractive index of a material of said layer measured at light wavelength of 555 nm.

A light source based on at least one UV LED, said light source comprising:

• a LED emitting UV radiation;
• a shaped structure that comprises a substantially transparent molding or casting material, said shaped structure covering said LED;
• particles of at least one phosphor that is excitable by said UV radiation, said phosphor disposed in a vicinity of said LED to receive said UV radiation and to convert said UV radiation to visible light, said particles of said phosphor dispersed in a portion of said molding or casting material;
• and
• a UV reflector comprising a plurality of layers of materials having at least alternating first and second refractive indices, said first refractive index being smaller than said second refractive index, said UV reflector being disposed on said shaped structure in a direction of a viewer;
• wherein a first layer of said plurality of layers is disposed adjacent to said shaped structure, said first layer of said plurality of layers comprises a material having said first refractive index, said first layer receives an incident light traversing said shaped structure, and said UV reflector comprises a plurality of protrusions formed on a surface of said UV reflector on which said incident light impinges.

A light source based on at least one UV LED, said light source comprising:

• a LED emitting UV radiation;
• a shaped structure that comprises a substantially transparent molding or casting material, said shaped structure covering said LED;
• particles of at least one phosphor that is excitable by said UV radiation, said phosphor disposed in a vicinity of said LED to receive said UV radiation and to convert said UV radiation to visible light;
• particles of at least one UV-radiation scattering material disposed among said particles of said phosphor, said particles of said phosphor and said particles of said UV-radiation scattering material being dispersed in a portion of said molding or casting material;
• and
• a UV reflector comprising:
• a plurality of layers of materials having at least alternating first and second refractive indices, said first refractive index being smaller than said second refractive index;
• and
• a plurality of protrusions formed on a surface of said UV reflector adjacent to said shaped structure;
• said UV reflector being disposed on said shaped structure in a direction of a viewer.