Luminaire device

• US 6,044,196 A
• Filed: 12/29/1997
• Issued: 03/28/2000
• Est. Priority Date: 03/23/1992
• Status: Expired due to Term

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Company
• Inventors: Winston, Roland, Emmons, Robert M., Gleckman, Philip, Holman, Robert L., Jacobson, Benjamin A.
• Primary Examiner(s): Palmer, Phan T. H.
• Application Number:
  US08/999,149
• Time in Patent Office: 820 Days
• Field of Search: 385/43, 385/129, 385/130, 385/131, 385/146, 385/147, 385/901, 385/140, 359/831, 359/833, 359/834, 359/869, 362/554, 362/556, 362/560, 349/61, 349/70, 349/56, 349/159, 349/164, 349/121, 349/117
• US Class Current: 385/146
• CPC Class Codes: F21V 5/02 of prismatic shape F21V5/04 takes precedence
• CPC Class Codes: G02B 6/0001 specially adapted for lighting devices or systems lighting or signalling on vehicles using light guides B60Q1/00; lighting devices for vehicle dashboards B60Q3/10; lighting devices for vehicle interior using light guides B60Q3/62; lighting devices mounted on the vehicle rear part using light guides F21S43/235; measuring arrangements having light conducting pointers G01D13/265; illumination of liquid crystal displays G02F1/1336; illuminated signs G09F13/00
• CPC Class Codes: G02B 6/0016 Grooves, prisms, gratings, scattering particles or rough surfaces
• CPC Class Codes: G02B 6/002 by shaping at least a portion of the light guide, e.g. with collimating, focussing or diverging surfaces
• CPC Class Codes: G02B 6/0021 for housing at least a part of the light source, e.g. by forming holes or recesses
• CPC Class Codes: G02B 6/0023 provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
• CPC Class Codes: G02B 6/0025 Diffusing sheet or layer; Prismatic sheet or layer
• CPC Class Codes: G02B 6/0031 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0038 Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide
• CPC Class Codes: G02B 6/0046 Tapered light guide, e.g. wedge-shaped light guide
• CPC Class Codes: G02B 6/0051 Diffusing sheet or layer
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0056 for producing polarisation effects, e.g. by a surface with polarizing properties or by an additional polarizing elements
• CPC Class Codes: G02B 6/4298 coupling with non-coherent light sources and/or radiation detectors, e.g. lamps, incandescent bulbs, scintillation chambers
• CPC Class Codes: G02F 1/133536 Reflective polarizers G02F1/13362 takes precedence
• CPC Class Codes: G02F 1/13355 Polarising beam splitters [PBS]
• CPC Class Codes: G02F 1/13362 providing polarized light, e.g. by converting a polarisation component into another one
• CPC Class Codes: G09F 13/00 Illuminated signs; Luminous advertising G09F9/00, G09F11/00 take precedence; control of displays in general using static means to present variable information G09G
• CPC Class Codes: G09F 13/0409 Arrangements for homogeneous illumination of the display surface, e.g. using a layer having a non-uniform transparency arrangements of reflectors G09F13/14
• CPC Class Codes: G09F 2013/05 : indicating exit way or orientation
• CPC Class Codes: G09F 2013/1827 : Prismatic window
• CPC Class Codes: Y10S 385/901 : Illuminating or display apparatus

Abstract

An optical device for collecting light and selectively outputting or concentrating the light. A layer has an optical index of referaction n₁, and top, bottom and side surfaces defining an angel of inclination φ. A back surface spans the top, bottom and side surface. A first layer is coupled to the bottom surface of the layer and has an index of refraction n₂. The first layer index n₂ causes light input through the back surface of the layer to be preferentially output into the first layer. A second layer is coupled to the bottom of the first layer and selectively causes output of light into ambient. Additional layers, such as alight polarization layer, a polarization converting layer and a post LCD diffuser layer can be used to make preferential use of polarized light of diffuse light having passed through the LCD layer to enhance viewing of the output light.

Claims

1. An optical device for operating on light from a source and for selectively outputting light for Lusage, comprising:

a base layer having at least a first and second surface, said base layer further including a back surface spanning said first and second surfaces, and the light exiting said base layer when the light being reflected therein decreases its angle relative to a normal to at least one of said first and second surfaces at the point of light incidence and achieves an angle of incidence less than a critical angle θ

_c relative to the normal at the point of light incidence on said surfaces;

first layer means disposed beyond at least one of said first and second surfaces relative to said base layer and for enabling light to enter and pass across said first layer means after output from said base layer when the light in said base layer achieves the angle of incidence less than the critical angle θ

_c characteristic of an interface between said base layer and said first layer;

a polarization splitting layer comprised of a multi-layer polymer film for preferably outputting light of a first polarization state compared to a second polarization state, said splitting layer disposed beyond at least one of said first and second surfaces relative to said base layer and said splitting layer further enabling reflection of at least part of the light having the second polarization state; and

an LCD layer for receiving the light previously encountering said polarization splitting layer and for processing the light to output light of the preferred first polarization state for usage.

2. An optical device for operating on light from a source and for selectively outputting light for usage, comprising:

a base layer having at least a first and second surface, said base layer further including a back surface spanning said first and second surfaces, and the light exiting said base layer when the light being reflected therein decreases its angle relative to a normal to at least one of said first and second surfaces at the point of light incidence and achieves an angle of incidence less than a critical angle θ

_c relative to the normal at the point of light incidence on said surfaces;

first layer means disposed beyond at least one of said first and second surfaces relative to said base layer and for enabling light to enter and pass across said first layer means after output from said base layer when the light in said base layer achieves the angle of incidence less than the critical angle θ

_c characteristic of an interface between said base layer and said first layer; and

a polarization recycling cavity including said base layer, said first layer means and a reflector layer enabling reflection of the light from said first layer means and at least partial conversion of light of a second polarization state to light of a preferred first polarization state.

3. The optical device as defined in claim 2 further including means for providing a hologram layer responsive to the light from said polarization recycling cavity to generate a hologram image.

4. An optical device for operating on light from a source and for selectively outputting light for usage, comprising:

a base layer having at least a first and second surface, said base layer further including a back surface spanning said first and second surfaces, and the light exiting said base layer when the light being reflected therein decreases its angle relative to a normal to at least one of said first and second surfaces at the point of light incidence and achieves an angle of incidence less than a critical angle θ

_c relative to the normal at the point of light incidence on said surfaces;

first layer means disposed beyond at least one of said first and second surfaces relative to said base layer and for enabling light to enter and pass across said first layer means after output from said base layer when the light in said base layer achieves the angle of incidence less than the critical angle θ

_c characteristic of an interface between said base layer and said first layer; and

a polarization recycling cavity including said base layer, said first layer means and a partial reflecting layer for causing at least partial conversion of light of a second polarization state to light of a preferred first polarization state.

5. The optical device as defined in claim 4 wherein said layer for at least partial conversion of light comprises a polarization converter layer.

6. The optical device as defined in claim 5 wherein said layer for at least partial conversion comprises a layer having an optical characteristic selected from the group consisting of birefringence, a total internal reflecting cavity, a prismatic reflector and a metallic reflector.

7. The optical device as defined in claim 4 wherein said layer for at least partial conversion of light comprises at least one of a prismatic redirecting layer and a binary optics layer.

8. The initial device as defined in claim 4 further including a BEF layer laminated to said polarization converter layer.

9. An optical device for operating on light from a source and for selectively outputting light for usage, comprising:

a base layer having at least a first and second surface, said base layer further including a back surface spanning said first and second surfaces, and the light exiting said base layer when the light being reflected therein decreases its angle relative to a normal to at least one of said first and second surfaces at the point of light incidence and achieves an angle of incidence less than a critical angle θ

_c relative to the normal at the point of light incidence on said surfaces;

first layer means disposed beyond at least one of said first and second surfaces relative to said base layer and for enabling light to enter and pass across said first layer means after output from said base layer when the light in said base layer achieves the angle of incidence less than the critical angle θ

_c characteristic of an interface between said base layer and said first layer;

a polarization recycling cavity comprised of means for diffusely reflecting light repeatedly and for progressively converting the light to the first polarization state; and

layer means for extracting light from said optical device for output and use.

10. The optical device as defined in claim 9 wherein said layer means for extracting light includes a redirecting layer comprised of a hologram.

11. The optical device as defined in claim 9 further including an LCD layer for receiving the light from said polarization recycling cavity and further processing the light to output light of the first polarization state.

12. An optical device for operating on light from a source and for selectively outputting light for usage, comprising:

a base layer having at least a first and second surface, said base layer further including a back surface spanning said first and second surfaces, and the light exiting said base layer when the light being reflected therein decreases its angle relative to a normal to at least one of said first and second surfaces at the point of light incidence and achieves an angle of incidence less than a critical angle θ

_c relative to the normal at the point of light incidence on said surfaces;

first layer means disposed beyond at least one of said first and second surfaces relative to said base layer and for enabling light to enter and pass across said first layer means after output from said base layer when the light in said base layer achieves the angle of incidence less than the critical angle θ

_c characteristic of an interface between said base layer and said first layer; and

a polarization recycling cavity comprised of said base layer constructed of birefringent material and said first layer means and said cavity causing at least partial conversion of light of a second polarization state to light of a preferred first polarization state.

13. An optical device for operating on light from a source and for selectively outputting light for usage, comprising:

a base layer having at least a first and second surface, said base layer further including a back surface spanning said first and second surfaces, and the light exiting said base layer when the light being reflected therein decreases its angle relative to a normal to at least one of said first and second surfaces at the point of light incidence and achieves an angle of incidence less than a critical angle θ

_c relative to the normal at the point of light incidence on said surfaces;

first layer means disposed beyond at least one of said first and second surfaces relative to said base layer and for enabling light to enter and pass across said first layer means after output from said base layer when the light in said base layer achieves the angle of incidence less than the critical angle θ

_c characteristic of an interface between said base layer and said first layer; and

a polarization splitting layer for processing the light to output light of a preferred first polarization state by separating out light of a second polarization state, said polarization splitting layer selected from the group consisting of a layer having scattering centers, a layer for generating diffraction, a layer of liquid crystals for reflecting light of selected polarization state and a Brewster splitter film.

14. The optical device as defined in claim 13 wherein said base layer includes a scattering component selected from the group consisting of a region of variable index of refraction, a prismatic layer, a hologram and a plurality of diffuse scattering centers.

15. An optical device for operating on light from a source and for selectively outputting light for usage, comprising:

a base layer having at least a first and second surface, said base layer further including a back surface spanning said first and second surfaces, and the light exiting said base layer when the light being reflected therein decreases its angle relative to a normal to at least one of said first and second surfaces at the point of light incidence and achieves an angle of incidence less than a critical angle θ

_c relative to the normal at the point of light incidence on said surfaces, and said base layer further providing an optical behavior following an adiabatic invariance such that a cross-sectional area A(z) of said base layer varies with a direction z of said base layer to provide a correlated value of L(z) which is the direction cosine in the direction normal to at least one of said first and second surfaces, thereby causing a variation in point of light escape from said base layer;

first layer means disposed beyond at least one of said first and second surfaces relative to said base layer and for enabling light to enter and pass across said first layer means after output from said base layer when the light in said base layer achieves the angle of incidence less than the critical angle θ

_c characteristic of an interface between said base layer and said first layer; and

a polarization recycling cavity including said base layer, said first layer means and a partial reflecting layer for causing at least partial conversion of light of a second polarization state to light of a preferred first polarization state.

16. The optical device as defined in claim 15 wherein said base layer comprises an initial portion adjacent said back surface with said initial portion having a non-monotonic varying cross-sectional area, thereby controlling light distribution output from said optical device.

17. The optical device as defined in claim 16 wherein the cross-sectional area and range of angular output for the light are adiabatically controlled to achieve a selected light output.

18. The optical device as defined in claim 15 further including a light source reflector selected from the group consisting of a CPC, a CHC, an involute of the light source and a non-imaging illuminator.

19. The optical device as defined in claim 15 wherein the adiabatic invariance of a wedge form of said base layer is described by:

##EQU14## where said A(z) is the wedge cross-section at the direction z, P is the illuminance power, L_o is the direction cosine at z=o, n₁ is the index of refraction for the base layer and n₂ is the index of refraction for the first layer means.

20. The optical device as defined in claim 15 wherein A(z)cos θ

_c,(z) is approximately equal to A_o L_o, where A_o is the cross-section at z=o and L_o in the direction cosine of θ

_c at z=o.

21. The optical device as defined in claim 15 where the adiabatic invariance is defined by a constant value times nk_z dz which product is approximately a constant, and where k_z is a direction cosine along the z direction, and n is an index of refraction as a function of x, y and z.

22. An optical device for operating on light from a source and for selectively outputting light to a viewer, comprising:

a base layer having at least a first and second surface, said base layer further including a back surface spanning said first and second surfaces, and the light exiting said base layer when the light being reflected therein decreases its angle relative to a normal to at least one of said first and second surfaces at the point of light incidence and achieves an angle of incidence less than a critical angle θ

_c relative to the normal at the point of light incidence on said surfaces;

first layer means disposed beyond at least one of said first and second surfaces relative to said base layer and for enabling light to enter and pass across said first layer means after output from said base layer when the light in said base layer achieves the angle of incidence less than the critical angle θ

_c characteristic of an interface between said base layer and said first layer;

second layer means for preferably outputting light of a first polarization state compared to a second polarization state, said second layer means disposed beyond at least one of said first and second surfaces relative to said base layer and said second layer means further enabling reflection of at least part of the light having the second polarization state;

light control layer means for at least one of redirecting and diffusing light output from said first layer means, thereby providing light of controlled angular distribution; and

imaging layer means for forning an image from the light of the first polarization state for display to the viewer.