Illumination system with remote phosphor layer and/or scattering layer

Patent metadata

Field	Value
Publication number	US-9250470-B2
Application number	US-201013146135-A
Country	US
Kind code	B2
Filing date	Jan 21, 2010
Priority date	Jan 28, 2009
Publication date	Feb 2, 2016
Grant date	Feb 2, 2016

Abstract

The invention relates to an illumination system ( 10, 12 ), to a remote phosphor layer ( 30; 32, 34 ), to a scattering layer ( 32 ), to a luminaire ( 100 ), to a display device ( 300 ) and to a method of at least partially correcting a light emission characteristic of at least one light source ( 22 ) in the illumination system. The illumination system comprises an array of light sources ( 20 ) and a remote phosphor layer and/or a scattering layer arranged between the array of light sources and a light output window ( 40 ) for emitting the light from the light sources. At least one light source of the array of light sources comprises a light emission characteristic different from the other light sources of the array of light sources. The luminescent material ( 52, 54 ) is distributed across the remote phosphor layer and/or the scattering structures ( 52 ) and/or scattering material ( 52 ) are distributed across the scattering layer for compensating at least partially the difference in light emission characteristic of the at least one light source.
The effect of the illumination system according to the invention is that the deviation of the at least one light source can be compensated, and as such, binning of light sources may be omitted.

First claim

The invention claimed is:

1. An illumination system comprising:
an array of light sources and a remote phosphor layer and scattering layer arranged between the array of light sources and a light output window for emitting the light from the light sources, wherein a majority of the array of light sources are made to and include a first standard comprising a first light emission characteristic,
at least one light source of the array of light sources comprising a light emission characteristic different from the majority of the array of light sources with the first light emission characteristic,
the remote phosphor layer and scattering layer being arranged at a distance from the array of light sources, the remote phosphor layer comprising luminescent material arranged for converting at least a part of the light emitted by the light sources into light of a different color, the scattering layer comprising scattering structures and/or scattering material arranged for scattering at least a part of the light emitted by the light sources, the luminescent material being distributed across the remote phosphor layer and the scattering structures and/or scattering material being distributed across the scattering layer in a different manner directly between the at least one light source and the light output window as compared to between the majority of the array of light sources with the first light emission characteristic and the light output window based on a determination of a distribution of the luminescent material and the scattering structures and/or scattering material required for compensating at least partially the difference in light emission characteristic of the at least one light source.

2. Illumination system as claimed in claim 1 , wherein the light emission characteristic is selected from the group consisting of: light intensity, light color, and angular emission profile.

3. Illumination system as claimed in claim 1 , wherein the distribution of the luminescent material comprises local variations of the luminescent material for at least partially compensating the difference in light emission characteristic, and/or wherein the distribution of the scattering structures and/or scattering material comprises local variations for at least partially compensating the difference in light emission characteristic, the local variations comprising any of:
varying a density of the luminescent material across the remote phosphor layer, and/or varying a density of the scattering structures and/or scattering material across the scattering layer,
varying a thickness of the luminescent material across the remote phosphor layer, and/or varying a thickness of the scattering structures and/or scattering material across the scattering layer,
varying a mixture of different phosphor materials and/or scattering material in the luminescent material across the remote phosphor layer, the luminescent material comprising a mixture of different phosphor materials and/or scattering material, each specific phosphor material absorbing a specific part of the light emitted by the light sources and emitting light of a specific color,
varying scattering and/or reflection properties across the remote phosphor layer for altering a length of an optical path through the remote phosphor layer.

4. Illumination system as claimed in claim 1 , wherein a combination of the array of light sources and the remote phosphor layer and scattering layer are configured for generating a substantially uniform light distribution across the light output window.

5. Illumination system as claimed in claim 4 , wherein the remote phosphor layer and/or the scattering layer are movable inside the illumination system for optimizing the uniformity of the light distribution across the light output window.

6. Illumination system as claimed in claim 1 , wherein the illumination system further comprises a plurality of remote phosphor layers, each arranged between the array of light sources and the light output window, each remote phosphor layer comprising a specific luminescent material for absorbing a specific part of the light emitted by the light sources and emitting light of a specific color.

7. Illumination system as claimed in claim 6 , wherein the plurality of remote phosphor layers are applied on a single carrier material.

8. Illumination system as claimed in claim 1 , wherein the luminescent material is a printable luminescent material for generating the distribution across the remote phosphor layer via a printing process, and/or wherein the scattering material is a printable scattering material for generating the distribution across the scattering layer via the printing process.

9. Illumination system as claimed in claim 1 , wherein the array of light sources comprises an array of light emitting diodes.

10. Illumination system as claimed in claim 1 , wherein the light sources in the array of light sources emit light having a central wavelength in a range between 400 nanometers and 490 nanometers.

11. Method of at least partially correcting a light emission characteristic of at least one light source in an illumination system, the illumination system comprising an array of light sources and a remote phosphor layer and/or a scattering layer comprising scattering structures and/or scattering material arranged between the array of light sources and a light output window for emitting the light from the light sources, wherein a majority of the array of light sources are made to and include a first standard comprising a first light emission characteristic and the at least one light source comprising a light emission characteristic different from the a majority of the array of light sources with the first light emission characteristic, wherein the method comprises a step of:
determining a variation of the emission characteristic across the light output window of the illumination system before applying the remote phosphor layer and/or scattering layer,
determining a distribution of the luminescent material and/or scattering structures and/or scattering material required for compensating the difference in light emission characteristic of the at least one light source,
applying the luminescent material according to the determined distribution for generating the remote phosphor layer for compensating at least partially the difference in light emission characteristic, and/or applying the scattering structures and/or scattering material according to the determined distribution for generating the scattering layer for compensating at least partially the difference in light emission characteristic, wherein the steps of applying comprise distributing the luminescent material across the remote phosphor layer and the scattering structures and/or scattering material across the scattering layer in a different manner directly between the at least one light source and the light output window as compared to between the majority of the array of light sources with the first light emission characteristic and the light output window, and
applying the remote phosphor layer and/or the scattering layer to the illumination system.

12. Illumination system as claimed in claim 1 , wherein the scattering layer further comprises a scattering material.

13. Illumination system as claimed in claim 12 , wherein the scattering material is a printable scattering material for generating the distribution across the scattering layer via the printing process.

14. Illumination system as claimed in claim 1 , wherein the scattering structures comprise structures selected from the group consisting of scratches, indentations, and dots.

1

Assignees

• Van Dijk Gerardus Arnoldus Rita
• Van Der Putten Andreas Martinus Theodorus Paulus
• Wegh Rene Theodorus
• Peeters Martinus Petrus Joseph
• Hendriks René Jan
• Koninkl Philips Nv

Inventors

• Van Dijk Gerardus Arnoldus Rita
• Van Der Putten Andreas Martinus Theodorus Paulus
• Wegh Rene Theodorus
• Peeters Martinus Petrus Joseph
• Hendriks René Jan

Classifications

• G02F1/133603 Primary

  with LEDs · CPC title

• H05B33/02

  Details · CPC title

• F21K2/06

  using chemiluminescence · CPC title

• G02F1/133611

  including means for improving the brightness uniformity · CPC title

• F21S2/005

  of modular construction · CPC title