ULTRA-THIN BACKLIGHT

• US 20110085112A1
• Filed: 10/18/2010
• Published: 04/14/2011
• Est. Priority Date: 05/16/2001
• Status: Active Grant

• Current Assignee: Benzion Inditsky
• Original Assignee: Benzion Inditsky
• Inventors: Inditsky, Benzion
• Granted Patent: US 8,684,584 B2
• Time in Patent Office: Days
• US Class Current: 349/65
• CPC Class Codes: G02F 1/133606 including a specially adapted diffusing, scattering or light controlling members
• CPC Class Codes: G02F 1/133607 the light controlling member including light directing or refracting elements, e.g. prisms or lenses
• CPC Class Codes: G02F 1/133615 Edge-illuminating devices, i.e. illuminating from the side
• CPC Class Codes: H01L 33/58 Optical field-shaping elements

Abstract

A thin-profile, optically efficient lighting device for use with, among other things, flat information displays, includes a combination of two optically coupled light propagating structures. The first structure may be a compound hyperbolic-elliptic element, adapted to receive light from at least one light source, such as a light emitting diode, and inject it into the second structure, which generally is larger and has hyperbolic-elliptic shape and a plurality of flux extractors. The latter redirect the light flux so that it propagates out of the second structure with a desired luminance and/or intensity distribution in a direction that is essentially perpendicular to the surface of the second structure. The flux extractors may also be of the active, i.e. wavelength-converting, type.

Claims

1. An apparatus to serve for display or lighting, comprising:

a wave guide with at least one edge and two faces, at least one of said faces including a doubly curved wedge light guiding arrangement;

at least one light source, coupled to one of the faces of the wave guide;

at least one passive or/and active light extractor, disposed integrally to one or both of the faces of the wave guide; and

a reflector, disposed proximate to at least one of the faces;

wherein said light guiding arrangement has an inclination angle that diminishes as a function of distance from each of said light sources along both coordinate axes of the respective face.

2. The apparatus of claim 1, further including a foconic coupler disposed between any of said light sources and the respective face of the wave guide.

3. The apparatus of claim 2, configured to serve as a backlight for a display device.

5. An apparatus as in claim 1, wherein any of said extractors include a thin layer, a solution, a suspension or a compound of passive light scattering agents or of active, wavelength converting, agents, roughened surfaces or a mixture of any of these means.

6. An apparatus as in claim 1, wherein said light source includes a ultraviolet, blue, white or tri-color (Red Green Blue) radiator, having a single or multiple escape cones.

7. An apparatus as in claim 2, wherein said foconic coupler and said doubly curved wave guide form a symmetrical compound surface having multiple segments, with mutually different curvatures.

8. An apparatus as in claim 7, wherein at least two of said segments are hyperbolic.

9. An apparatus as in claim 8, wherein at least one segment is hyperbolic and at least one other segment is elliptic.

10. An apparatus as in claim 7, wherein at least one of said segments includes a reflector.

11. An apparatus as in claim 2, wherein said foconic coupler and said doubly curved wave guide form an asymmetrical compound surface, having mutually different curvatures along different horizontal coordinate axes.

12. An apparatus as in claim 11, wherein said compound surface has multiple segments with mutually different curvatures along each of said coordinate axes.

13. An apparatus as in claim 12, wherein at least two of said segments are hyperbolic along each of said coordinate axes.

14. An apparatus as in claim 12, wherein, along each of said coordinate axes, at least one segment is hyperbolic and at least one other segment is elliptic.

15. An apparatus as in claim 2, wherein said foconic coupler has a compound forward-extracting elliptic surface, forming an asymmetrical lens that has mutually different curvatures along different coordinate axes of said faces.

16. An apparatus as in claim 2, wherein said foconic coupler has a two-dimensional linear shape, formed by a translation of a constant vertical cross-section along a horizontal axis

17. A lighting device as in claim 2, wherein said foconic coupler has a truncated shape, with an apex having a planar, elliptic or hyperbolic surface.

18. An apparatus as in claim 17, wherein said apex surface is transparent.

19. An apparatus as in claim 17, wherein said apex surface has a reflective layer.

21. An apparatus as in claim 1, wherein said wave guide has edges formed by coaxial spherical segments alternating with radial linear segments.

22. An apparatus as in claim 2, wherein said wave guide is substantially thicker in regions that are not in contact with said foconic couplers, thereby forming an Induced Photonic Recycling Chamber.

23. An apparatus as in claim 1, wherein said light source is shaped as a tetrahedron with a vertical aspect ratio of between 0.5 and 3.

24. An apparatus as in claim 23, wherein said tetrahedron is isosceles.

25. An apparatus as in claim 23, wherein said tetrahedron is a right angle tetrahedron, having a right angle base.

26. An apparatus as in claim 1, wherein said light source is shaped as a double right angle tetrahedron with a vertical aspect ratio of between 0.5 and 3.

27. An apparatus as in claim 23, wherein said tetrahedron is truncated.

28. An apparatus as in claim 2, wherein any of the foconic couplers is shaped as a tetrahedron.

29. An apparatus as in claim 28 wherein any of the foconic couplers has a refraction index of between 1.5 and 2.4.

30. An apparatus as in claim 28, wherein said foconic coupler is encapsulated in an inverted truncated tetrahedral lens, having an essentially larger size and an essentially lower refraction index.

31. An apparatus as in claim 1, wherein said active extractors are deposited with a non-uniform two-dimensional density distribution.

32. An apparatus as in claim 1, wherein some of said active extractors differ from others in the wavelength of the emitted light and are deposited correspondingly in different regions of said wave guide.

33. An apparatus as in claim 2, further comprising two additional wave guides, similar to said wave guide, all three of said wave guides being arranged in a vertical stack, separated by air interfaces.

34. An apparatus as in claim 1, wherein one of the faces of said waveguide is roughened by a two dimensional array of polyhedrons with a vertical aspect ratio of between 1.5 and 15.

4. A liquid crystal display device, comprising:

a liquid crystal display module; and

a backlight structure, including;

a light source,

a wave guide, including two faces,

a foconic coupler disposed between the light source and a face of the wave guide, and

a reflector disposed proximate to one of the faces of the wave guide;

20. An apparatus for use with a radiation- or lighting device comprising:

a radiation source with a refraction index N_em;

a plurality of dielectric materials with successively decreasing N_ex,n (N_em>

N_ex1>

N_ex,2>

. . . N_ex,n≧

1), first material being in optical contact with said radiation source and each subsequent material being in direct optical contact, without an air interface, with materials adjacent thereto, wherein said source and materials have a progressively increasing minimal projected surface area, scaled according to an Extraction Invariant, which is expressed as;

S_ex,n≧

S_ex,n-1*(N_n-1/N_n)²

and

S_ex,n≧

S_em*(N_em/N_ex,n)².