ILLUMINATION SYSTEM, LUMINAIRE AND BACKLIGHTING UNIT

• US 20100172152A1
• Filed: 05/26/2008
• Published: 07/08/2010
• Est. Priority Date: 05/29/2007
• Status: Active Grant

• Current Assignee: Signify Holding B.V. (Signify N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Boonekamp, Erik
• Granted Patent: US 8,425,101 B2
• Time in Patent Office: Days
• US Class Current: 362/609
• CPC Class Codes: F21V 11/02 using parallel laminae or strips, e.g. of Venetian-blind type F21V11/06 takes precedence
• CPC Class Codes: F21V 13/08 the elements being filters or photoluminescent elements and reflectors
• CPC Class Codes: F21V 13/10 the elements being reflectors and screens
• CPC Class Codes: F21V 7/0008 providing for indirect lighting
• CPC Class Codes: F21V 7/0025 Combination of two or more reflectors for a single light source array of reflectors for a cluster of light sources F21V7/0083
• CPC Class Codes: F21V 9/30 Elements containing photoluminescent material distinct from or spaced from the light source shades F21V1/17; globes, bowls or cover glasses F21V3/08, F21V3/12; refractors F21V5/10; reflectors F21V7/26, F21V7/30; elements with provision for controlling the spectral properties or intensity F21V9/40
• CPC Class Codes: F21Y 2103/10 comprising a linear array of point-like light-generating elements
• CPC Class Codes: F21Y 2103/33 annular
• CPC Class Codes: F21Y 2113/13 comprising an assembly of point-like light sources
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G02F 1/13336 Combining plural substrates to produce large-area displays, e.g. tiled displays
• CPC Class Codes: G02F 1/133507 Films for enhancing the luminance
• CPC Class Codes: G02F 1/133606 including a specially adapted diffusing, scattering or light controlling members
• CPC Class Codes: G02F 1/133615 Edge-illuminating devices, i.e. illuminating from the side
• CPC Class Codes: G02F 1/133617 Illumination with ultraviolet light; Luminescent elements or materials associated to the cell
• CPC Class Codes: G02F 1/133621 providing coloured light G02F1/133617, G02F1/133533 take precedence

Abstract

The invention relates to an illumination system (2), aluminaire (2), a backlighting system and a display device. The illumination system according to the invention comprises a light exit window (30) for emitting light from the illumination system, and a diffuse reflecting screen (40) arranged opposite the light exit window. The illumination system further comprises a light source (20) which is arranged for indirect illumination of the light exit window via the diffuse reflecting screen. The light source is arranged near an edge of the light exit window on an imaginary plane (22) arranged substantially parallel to the light exit window and emits light away from the light exit window. The illumination system further comprises an edge wall (62) comprising a specular reflecting mirror (60) being concavely shaped for reflecting at least part of the light emitted by the light source towards the diffuse reflecting screen. The effect of the illumination system according to the invention is that the use of the specular reflecting mirror enables a controlled reflection of the part of the light emitted by the light source towards the diffuse reflecting screen.

Claims

1. An illumination system having a light exit window for emitting light from the illumination system, the illumination system comprising:

a diffuse reflecting screen arranged opposite the light exit window,

a light source being arranged for indirect illumination of the light exit window via the diffuse reflecting screen, the light source being arranged near an edge of the light exit window on an imaginary plane substantially parallel to the light exit window, the light emitted from the light source having an angular distribution around a central vector pointing away from the light exit window, the central vector being inclined with respect to a normal axis of the imaginary plane for reducing a glare of the illumination system, and

an edge wall arranged between the diffuse reflecting screen and the light exit window, the edge wall comprising a specular reflecting mirror being concavely shaped for reflecting at least part of the light emitted by the light source towards the diffuse reflecting screen.

3. Illumination system as claimed in claim 1, wherein the specular reflecting mirror comprises a shape for generating a substantially uniform illumination of the part of the diffuse reflecting screen.

4. Illumination system as claimed in claim 1, wherein the specular reflecting mirror comprises a paraboloidal shape.

5. Illumination system as claimed in claim 1, wherein the light source is arranged on a ridge arranged at the edge of the light exit window, the specular reflecting mirror being arranged at a side of the light source facing away from the light exit window.

6. Illumination system as claimed in claim 1, wherein the diffuse reflecting screen comprises a structured reflecting surface.

7. Illumination system as claimed in claim 6, wherein the structured reflecting surface comprises a plurality of elongated prismatic, pyramidal, or conical structures.

8. Illumination system as claimed in claim 1, wherein the diffuse reflecting screen comprises a collimating plate a redirecting foil, or a plurality of lamellae (44) arranged substantially perpendicular to the diffuse reflecting screen.

9. Illumination system as claimed in claim 1, wherein a ratio between a height (h2) of the illumination system and a width (w) of the light exit window is larger than or equal to 1/20, wherein the height (h2) is a dimension of the illumination system substantially perpendicular to the light exit window and wherein the width (w) of the light exit window is a minimum dimension of the light exit window substantially parallel to the light exit window.

10. Illumination system as claimed in claim 1, wherein the illumination system comprises a remote phosphor layer arranged on the diffuse reflecting screen and/or on the light exit window, the remote phosphor layer being a layer comprising a luminescent material for converting at least part of the light emitted by the light source into light having a different color.

11. Illumination system as claimed in claim 1, wherein the illumination system further comprises an array of further light sources arranged on the diffuse reflecting screen for direct illumination of the light exit window, a color of the light emitted by the light source being different from a color of the light emitted by the array of further light sources.

12. Illumination system as claimed in claim 1, wherein the light exit window comprises a diffuser, or a Brightness Enhancement Film, or Micro Lighting Optics, or a prismatic sheet, or a plurality of lamellae arranged substantially perpendicular to the light exit window

2. (canceled)

13-17. -17. (canceled)