Bidirectional LED light sheet

• US 8,192,051 B2
• Filed: 11/01/2010
• Issued: 06/05/2012
• Est. Priority Date: 11/01/2010
• Status: Active Grant

• Current Assignee: Quarkstar LLC
• Original Assignee: Quarkstar LLC
• Inventors: Dau, Wilson, Lerman, Louis, York, Allan Brent
• Primary Examiner(s): Negron, Ismael
• Application Number:
  US12/917,327
• Publication Number:
  US 20110063838A1
• Time in Patent Office: 582 Days
• Field of Search: 362/97.3, 362/147, 362/236, 362/240, 362/242, 362/244, 362/249.02, 362/249.06
• US Class Current: 362/249.02
• CPC Class Codes: F21K 9/60 Optical arrangements integrated in the light source, e.g. for improving the colour rendering index or the light extraction
• CPC Class Codes: F21S 8/04 intended only for mounting on a ceiling or the like overhead structures F21S8/02 takes precedence; details of ceiling bases F21V21/03
• CPC Class Codes: F21S 8/046 having multiple lighting devices, e.g. connected to a common ceiling base
• CPC Class Codes: F21S 8/06 by suspension
• CPC Class Codes: F21S 8/068 from a stretched wire
• CPC Class Codes: F21V 21/14 Adjustable mountings
• CPC Class Codes: F21V 21/16 using wires or cords
• CPC Class Codes: F21V 23/06 the elements being coupling devices , e.g. connectors
• CPC Class Codes: F21V 5/04 of lens shape
• CPC Class Codes: F21V 5/10 comprising photoluminescent material
• CPC Class Codes: F21V 7/00 Reflectors for light sources characterised by cooling arrangements F21V29/505
• CPC Class Codes: F21V 7/0016 on lighting devices that also provide for direct lighting, e.g. by means of independent light sources, by splitting of the light beam, by switching between both lighting modes
• CPC Class Codes: F21Y 2105/10 comprising a two-dimensional array of point-like light-generating elements
• CPC Class Codes: F21Y 2107/90 on two opposite sides of supports or substrates
• CPC Class Codes: F21Y 2109/00 Light sources with light-generating elements disposed on transparent or translucent supports or substrates
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 25/0756 Stacked arrangements of devices
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H05K 1/189 : characterised by the use of a flexible or folded printed circuit H05K3/326 takes precedence
• CPC Class Codes: H05K 2201/10106 : Light emitting diode [LED]

Abstract

A bidirectional light sheet including at least a first and second array of bare LED chips with top and bottom electrodes, where the arrays of LEDs are sandwiched between at least two transparent substrates having conductors bonded to the electrodes without wires to form the light sheet. The LEDs of the array are arranged within the light sheets to emit light from opposite surfaces of the light sheet to create a bidirectional light sheet. The bidirectional light sheet is suspended from a ceiling to be non-parallel to the ceiling.

Claims

1. A bidirectional lighting device for general illumination comprising:

a first plurality of first non-packaged light emitting diode (LED) dies arranged to emit light in a first direction and having electrodes;

a second plurality of second non-packaged light emitting diode (LED) dies arranged to emit light in a second direction different from the first direction and having electrodes;

at least a first substrate and a second substrate sandwiching the first plurality and second plurality of LED dies and forming a light emitting structure having a first light emitting surface outputting light from the lighting device in the first direction and an opposing second light emitting surface outputting light from the lighting device in the second direction different from the first direction;

conductors formed on at least one of the first substrate and second substrate electrically connected to the electrodes of the first plurality and the second plurality of LED dies without wires for connecting the first plurality and the second plurality of LED dies to a source of power; and

wherein the first substrate and the second substrate form a bidirectional light sheet, and

wherein the light sheet is affixed proximate to a ceiling such that the first and second light emitting surfaces are not parallel to the ceiling, and wherein some light from the bidirectional light sheet is directed towards the ceiling and some light from the bidirectional light sheet is directed towards a floor;

wherein the first substrate has first connection locations electrically connected to first conductors formed on the first substrate,

wherein each of the first plurality and the second plurality of LED dies has at least a first die electrode and a second die electrode, the first die electrode being formed on a primary light output surface of the LED die,

wherein some of the first plurality and the second plurality of LED dies have their first die electrode aligned with and electrically connected to an associated one of the first connection locations on the first substrate without wire bonds,

wherein the second substrate has second connection locations electrically connected to second conductors formed on the second substrate,

wherein other ones of the first plurality and second plurality of LED dies have their first die electrode aligned with and electrically connected to an associated one of the second connection locations on the second substrate without wire bonds, and

wherein the first substrate and the second substrate have light output surfaces for emitting light in opposing directions from at least the primary light output surfaces of the first plurality and the second plurality of LED dies.

2. The device of claim 1 wherein the light sheet is affixed to the ceiling such that the first and second light emitting surfaces are substantially perpendicular to the ceiling.

3. The device of claim 1 wherein the light sheet is suspended from the ceiling by wires such that the first and second light emitting surfaces are substantially perpendicular to the ceiling.

4. The device of claim 1 wherein an angle of the light sheet relative to the ceiling is adjustable.

5. The device of claim 1 further comprising lenses in the device that direct a peak intensity of light at a certain angle relative to the ceiling.

6. The device of claim 1 wherein the light sheet is one of a plurality of light sheets in a luminaire, wherein at least two of the light sheets emit a peak intensity of light at different angles.

7. The device of claim 1 further comprising two or more different optical elements in the device that direct light at different angles relative to the ceiling.

8. The device of claim 1 further comprising one or more intermediate layers between the first substrate and the second substrate.

9. The device of claim 1 wherein the first substrate and the second substrate directly contact each other with no intermediate layer between them.

10. The device of claim 1 further comprising at least a third substrate sandwiched between the first substrate and the second substrate, the third substrate having a reflective layer for reflecting light out through the first substrate and the second substrate.

11. The device of claim 1 further comprising a reflective layer between the first substrate and the second substrate, wherein some of the first plurality and the second plurality of LED dies are located between the reflective layer and a light output surface of the first substrate, and other ones of the first plurality and the second plurality of LED dies are located between the reflective layer and a light output surface of the second substrate.

12. The device of claim 1 wherein the light sheet is one of a plurality of light sheets in a luminaire, wherein a first side of the luminaire emits light from a first light sheet at a first peak intensity angle and emits light from a second light sheet at a second peak intensity angle, different from the first peak intensity angle.

13. The device of claim 12 wherein a second side of the luminaire, opposite the first side of the luminaire, emits light from a third light sheet at the first peak intensity angle and emits light from a fourth light sheet at a fourth peak intensity angle, different from the third peak intensity angle.

14. The device of claim 1 wherein at least some of the first plurality and the second plurality of LED dies are connected in series by the first conductors and the second conductors.

15. The device of claim 14 wherein the at least some of the first plurality and the second plurality of LED dies are connected in series by the first conductors and the second conductors interconnecting the first die electrodes to the second die electrodes.

16. The device of claim 1 wherein the bidirectional light sheet is curved and suspended from the ceiling.

17. The device of claim 16 wherein the bidirectional light sheet substantially forms a cylinder having sides substantially perpendicular to the ceiling.