LIGHT SOURCE COMPRISING A LIGHT EMITTER ARRANGED INSIDE A TRANSLUCENT OUTER ENVELOPE

• US 20120155059A1
• Filed: 04/23/2010
• Published: 06/21/2012
• Est. Priority Date: 05/04/2009
• Status: Active Grant

• Current Assignee: Signify Holding B.V. (Signify N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Hoelen, Christoph Gerard August, Wegh, Rene Theodorus, Duan, Xiaoqing, Rider, Timothy Howard, Shi, Lei, Ansems, Johannes Petrus Maria, Hoskens, Roger Cornelis Petrus, Ampalathumkal George, Nibu
• Granted Patent: US 9,175,817 B2
• Time in Patent Office: Days
• US Class Current: 362/84
• CPC Class Codes: F21K 9/23 Retrofit light sources for lighting devices with a single fitting for each light source, e.g. for substitution of incandescent lamps with bayonet or threaded fittings
• CPC Class Codes: F21K 9/232 specially adapted for generating an essentially omnidirectional light distribution, e.g. with a glass bulb
• CPC Class Codes: F21K 9/64 using wavelength conversion means distinct or spaced from the light-generating element, e.g. a remote phosphor layer
• CPC Class Codes: F21V 29/77 with essentially identical diverging planar fins or blades, e.g. with fan-like or star-like cross-section
• CPC Class Codes: F21V 3/00 Globes; Bowls; Cover glasses with refracting properties F21V5/00; with reflecting properties F21V7/00; characterised by cooling arrangements F21V29/506
• CPC Class Codes: F21V 3/02 characterised by the shape
• CPC Class Codes: F21V 3/12 the coatings comprising photoluminescent substances
• CPC Class Codes: F21Y 2107/40 on the sides of polyhedrons, e.g. cubes or pyramids
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]

Abstract

The invention relates to a light source (10, 12) comprising a light emitter (20) arranged inside a translucent outer envelope (30, 32). The light emitter comprising a light emitting device (40) and comprising a translucent inner envelope (50) at least partially surrounding the light emitting device, the translucent inner envelope comprising a diffuser. A diameter (d_i) of the translucent inner envelope is smaller than a diameter (d_o) of the translucent outer envelope. The translucent outer envelope is connected to a base (60) not being translucent. The translucent outer envelope further comprises a symmetry axis (S). An imaginary base-plane (P) is defined substantially perpendicular to the symmetry axis (S) and intersects with a connection point (C) being part of the translucent outer envelope. The connection point is a light transmitting part of the translucent outer envelope at an interface between the translucent outer envelope and the base at a furthest distance from a center (M) of the translucent outer envelope. The light emitter is arranged inside the translucent outer envelope at a distance from the imaginary base-plane away from the base.

An effect of the light source according to the invention is that the emission profile of the light source according to the invention is increased.

Claims

1. A light source comprising a light emitter arranged inside a translucent outer envelope,

the translucent outer envelope being connected to a base, and further comprising a symmetry axis, an imaginary base-plane being defined substantially perpendicular to the symmetry axis and intersecting with a connection point being part of the translucent outer envelope, the connection point being a light transmitting part of the translucent outer envelope at an interface between the translucent outer envelope and the base at a furthest distance from a center (M) of the translucent outer envelope,

the light emitter comprising a light emitting device and a translucent inner envelope at least partially surrounding the light emitting device, wherein the light emitting device is arranged on a substantially flat circuit board arranged substantially parallel to the imaginary base-plane, the translucent inner envelope comprising a diffuser for diffusing at least a part of the light emitted by the light emitting device, a diameter of the translucent inner envelope being smaller than a diameter of the translucent outer envelope,

the light emitter being arranged inside the translucent outer envelope at a distance from the imaginary base-plane away from the base.

2. Light source according to claim 1, wherein the diffuser comprises luminescent material for converting light emitted by the light emitting device into light of a longer wavelength.

3. Light source according to claim 1, wherein the light emitting device is a light emitting diode and/or a light emitting laser diode.

5. Light source according to claim 1, wherein an optical element is arranged inside the inner envelope for generating a batwing or butterfly shaped radiation profile from the light emitting device when viewed in a cross-sectional view through the symmetry axis (S) to enhance a relative level of radiation on the inner envelope at portions away from the top of the inner envelope, the top of the inner envelope being the part of the inner envelope intersecting with the symmetry axis.

6. Light source according to claim 1, wherein a diameter of the inner envelope is smaller than or equal to 70% of the diameter of the outer envelope.

7. Light source according to claim 1, wherein the inner envelope comprises a cut-out portion for accommodating the light emitting device, and wherein a diameter of the inner envelope is larger than a diameter of the cut-out portion, the diameter of the inner envelope being measured in a direction parallel to the direction for measuring the diameter of the cut-out portion.

8. Light source according to claim 1, wherein the inner envelope comprises a full spherical shape or a partial spherical shape.

9. Light source according to claim 1, wherein the inner envelope has a larger dimension in a direction parallel to the symmetry axis compared to a dimension in a direction perpendicular to the symmetry axis.

10. Light source according to claim 1, wherein the inner envelope and/or the outer envelope comprise an at least partially reflective layer.

11. Light source according to claim 10, wherein the at least partially reflective layer is arranged on a part of the inner envelope and/or on a part of the outer envelope.

12. Light source according to claim 1, wherein the light emitter is arranged on a connection element for connecting the light emitter to the base and for defining the distance between the light emitter and the imaginary base-plane.

13. Light source according to claim 12, wherein the distance between the light emitter and the imaginary base-plane is chosen to generate an emission distribution in a distribution plane of at least 220 degrees full width half maximum, the distribution plane being an imaginary plane intersecting with the symmetry axis.

14. Light source according to claim 12, wherein the connection element is a cone-shaped connection element widening from the light emitter towards the base for preventing light emitted by the light emitter toward the connection point to be obstructed by the connection element.

15. Light source according to claim 12, wherein the connection element is thermally connected to the light emitting device for extracting heat away from the light emitting device.

16. Light source according to claim 15, wherein the base further comprises a heat transfer means being thermally connected to the connection element.

17. Light source according to claim 16, wherein the heat transfer means comprises cooling fins extending in a direction parallel to the symmetry axis for allowing light to be emitted from the outer envelope through the gaps between the cooling fins.

18. Light source according to claim 1, wherein the outer envelope comprises a further diffuser for diffusing light transmitted through the outer envelope.

19. Light source according to claim 18, wherein the further diffuser comprises a diffusivity between 5 and 120 degrees Full Width at Half Maximum, the diffusivity being defined by a scattering behavior of a collimated pencil beam impinging on the diffuser and resulting in a spatial scattering of the impinging collimated pencil beam.

20. Light source according to claim 1 wherein a wall of the inner envelope facing the outer envelope comprises a diffusing layer.

21. Light source as claimed in claim 1, wherein:

the light source further comprises a surface comprising the light emitting device, the surface comprising a reflective layer and/or comprising further luminescent material, and/or

the light source further comprises a reflective layer and/or further luminescent material applied to non-translucent surfaces inside the outer envelope, and/or

the light emitting device comprises a plurality of light emitting diodes arranged at different angles with respect to the symmetry axis and/or with respect to each other, and/or

the light emitting device comprises a phosphor-enhanced light emitting device, and/or

the light emitting device is configured for emitting light of the color blue and wherein the inner envelope comprises luminescent material configured for absorbing light of the color blue and converting part of the absorbed light into light of the color yellow, and/or

the light emitting device is configured for emitting light of the color blue and light of the color red-orange, and wherein the inner envelope comprises luminescent material configured for absorbing light of the color blue and converting part of the absorbed light into light of the color yellow-green, and/or

a wall of the outer envelope facing the inner envelope comprises an even further luminescent layer for converting light emitted by the light emitter into light of a longer wavelength, and/or

a wall of the outer envelope facing the inner envelope comprises an organic lumophor layer for converting light emitted by the light emitter into light of a longer wavelength.

4. (canceled)