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Creating Unity with Phosphor

IP

US9677719

Owner

OSRAM GmbH

Filing Date

June 11, 2013

Priority Date

June 11, 2012

Portfolio

Lighting - OSRAM

Intro

This invention solves the problem of color variance between light emitted from an LED tube in different directions. The invention proposes a cover part surrounding the light source having different phosphor thickness in two different light emitting directions of the light source.

Claims

1. A light-emitting device, comprising: a substrate; a light source arranged on the substrate; and a cover part spaced a certain distance apart from t...
  1. A light-emitting device, comprising: a substrate; a light source arranged on the substrate; and a cover part spaced a certain distance apart from the light source and transmitting light emitted from the light source to outside, wherein the cover part comprises a first part, converting wavelengths of a part of light in light emitted from the light source and having different thicknesses at least in two different light-emitting directions of the light source; and a second part, having different thicknesses in the two different light-emitting directions to compensate the thicknesses of the first part, wherein the first part comprises a substrate and phosphors dispersed in the substrate and arranged on the outermost layer of the cover part, the second part made from a material the same as that of the substrate, and the second part is free from phosphor, and a sum of thickness of the first part and thickness of the second part is a fixed value.
  2. The light-emitting device according to claim 1, wherein the second part is configured upstream from the first part in a light path.
  3. The light-emitting device according to claim 1, wherein the first part and the second part are in close contact.
  4. The light-emitting device according to claim 1, wherein the first part has a non-uniform thickness corresponding to a luminous intensity spatial distribution of the light source.
  5. The light-emitting device according to claim 4, wherein thickness of the second part depends upon the thickness of the first part.
  6. The light-emitting device according to claim 1, wherein the light source is blue LEDs, and the first part comprises phosphors converting blue light to yellow light such that the light-emitting device emits white light.
  7. The light-emitting device according to claim 1, wherein the light source is ultraviolet LEDs, and the first part comprises phosphors converting ultraviolet to visible light such that the light-emitting device emits visible light.
  8. The light-emitting device according to claim 1, wherein a light transmission material is filled between the cover part and the light source.
  9. The light-emitting device according to claim 1, wherein the cover part partially encloses the light source, and a light incident surface or a light emergent surface of the cover part is a part of a cylindrical surface, a part of a spherical surface or a part of an ellipsoid surface.
  10. The light-emitting device according to claim 1, wherein a light incident surface or a light emergent surface of the cover part is a plane.
  11. The light-emitting device according to claim 1, wherein the first part and the second part are made in one piece.
  12. The light-emitting device according to claim 11, wherein the first part and the second part are made through a bi-material injection process or a bi-material extrusion process.
  13. Illuminating apparatus comprising a light-emitting device, the light-emitting device comprising: a substrate; a light source arranged on the substrate; and a cover part spaced a certain distance apart from the light source and transmitting light emitted from the light source to outside, wherein the cover part comprises a first part, converting wavelengths of a part of light in light emitted from the light source and having different thicknesses at least in two different light-emitting directions of the light source; and a second part, having different thicknesses in the two different light-emitting directions to compensate the thicknesses of the first part, wherein the first part comprises a substrate and phosphors dispersed in the substrate and arranged on the outermost layer of the cover part, the second part is made from a material the same as that of the substrate, and the second part is free from phosphor, and a sum of thickness of the first part and thickness of the second part is a fixed value. 
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Abstract

A light-emitting device may include a substrate, a light source arranged on the substrate, and a cover part spaced a certain distance apart from the l...
A light-emitting device may include a substrate, a light source arranged on the substrate, and a cover part spaced a certain distance apart from the light source and transmitting light emitted from the light source to outside. The cover part includes a first part, converting wavelengths of a part of light in light emitted from the light source and having different thicknesses at least in two different light-emitting directions of the light source, and a second part, having different thicknesses in the two different light-emitting directions to compensate the thicknesses of the first part.
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Light Expert :-)
May 27, 2018

This invention is related to LED lights. Existing lights have different luminous intensity in multiple directions resulting in emission of various light colors. Currently, lights use phosphor cover with non-uniform thickness to solve this problem, but light direction is changed when cover thickness is non-uniform and also, changes light intensity in different directions. Proposed LED lights have a light source arranged on a substrate and a cover spaced away from the light source. The cover is designed in two parts with different thickness in different directions keeping their sum constant in all directions so that uniform light intensity is achieved. First part has a substrate, and phosphors are arranged on outermost layer and second part is made from a substrate material but free from phosphor, so that uniform chroma and light-emitting performances can be obtained. Proposed LEDs are cost effective and can be fabricated using a bi-material injection process.
Applications: The invention may be implemented in LED lights, LED tubes, outdoor LED lights, LED luminaires, LED facility lights, decorative LED lights etc.
Companies: This invention may be implemented by lighting companies.

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