LIGHT EMITTING PLATE SYSTEM WITH IMPROVED TRANSPARENCY

• US 20090185383A1
• Filed: 09/20/2005
• Published: 07/23/2009
• Est. Priority Date: 09/29/2004
• Status: Abandoned Application

• Current Assignee: Koninklijke Philips N.V.
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Busselt, Wolfgang, Bertram, Dietrich, Bechtel, Helmut, Boerner, Herbert Friedrich, Meijers, Augustinus Gregorius Henricus, Jüstel, Thomas
• Application Number:
  US11/575,759
• Publication Number:
  US 20090185383A1
• Time in Patent Office: Days
• US Class Current: 362/311.10
• CPC Class Codes: G02B 6/0041 provided in the bulk of the light guide
• CPC Class Codes: G02B 6/005 provided by one optical element, or plurality thereof, placed on the light output side of the light guide

Abstract

The invention relates to a light emitting plate system (1), in which the plate (10) is equipped with at least one particle layer (40), the particle (50) of which have been designed to achieve an improved transparency and light extraction efficiency of the plate (10).

Claims

1. Light emitting plate system (1) comprising a plate (10) having a layer and/or window—

like configuration with a first surface (100) and a second surface (200) opposing to the first surface, a light source (20) which is located on the side of the plate (10) in such a way that most of the light, which is emitted from the light source (20), enters the plate in an angle which is somewhat perpendicular to the first (100) and second surface (200), characterized in that at least one particle layer (40) is provided at least partly on the first and/or second surface, whereby the features of particles (50) of the particle layer (40) have been matched in that way that the transparency of the light emitting plate system for light with a wavelength of ≧

380 nm to ≦

700 nm which enters the first or second surface in an angle of ≧

45 to ≦

90 thereof is ≧

0.5 to ≦

0.99.

2. Light emitting plate system according to claim 1, whereby the diffuse reflection of light with a wavelength of ≧

500 nm to ≦

600 nm which enters the first and/or second surface in an angle of ≧

45 to ≦

90 thereof is ≧

0% to ≦

10%.

3. Light emitting plate system according to claim 1, whereby the particles (50) of the particle layer (40) are embedded in a matrix, the matrix material preferably being selected from a group comprising glass, silicone, inorganic materials with an refractive index of ≧

1.0 and ≦

3.5, inorganic polymers, organic polymers, preferably with an refractive index of ≧

1.0 and ≦

3.5 or mixtures thereof.

4. Light emitting plate system according to claim 3, whereby the median particle diameter d of the particles (50) of the at least one particle layer (40) is from ≧

50 nm to

$\le <br><br><br><br>\frac{550<br><br><br><br>\mathrm{nm}}{n_{\mathrm{particle}}-n_{\mathrm{matrix}}}<br><br>$

whereby n_particle is the refractive index of the particles of the particle layer and n_plate is the refractive index of the matrix.

5. Light emitting plate system according to claim 1, whereby the scattering power sT, being the product of the scattering parameter s and the layer thickness T of the particles (50) of the at least one particle layer (40) is ≧

0 and ≦

0.24.

6. A light emitting plate system according to claim 1, whereby the thickness T of the particle layer (40) is ≧

2d and ≦

20 d, d being the median particle diameter of the particles (50) of the at least one particle layer (40).

7. A light emitting plate system according to claim 1, whereby the particles of the at least one particle layers are made out of a material chosen from a group comprising inorganic materials, organic materials and organic polymers, whereby the inorganic materials are preferably selected from a group comprising SiO₂, MgO, Al₂O₃, TiO₂, ZrO₂, sulphides, phosphates, borates, zeolithes or sodalites.

8. A light emitting plate system according to claim 1, the absorption a of the particles of the at least one particle layer for light in the wavelength region from 400 nm to 800 nm is 0≦

a≦

1 cm<sup>−

1</sup>, more preferred 0.01≦

a≦

0.5 cm<sup>−

1</sup> and most preferred 0.02≦

a≦

0.2 cm<sup>−

1</sup>.

9. A light emitting plate system according to claim 1, whereby the plate (10) is made out of a material chosen from a group comprising PMMA, PS, PTFE, PC, glass and mixtures thereof.

10. A system comprising a light emitting plate system according to any of the claim 1, the system being used in one or more of the following applications:

household applications

room separators in buildings

separation walls in transportation systems

shop applications

windows, especially windows for buildings

car windows

transparent roofs in buildings and vehicles