LED-based lamp including shaped light guide

1. A lamp ( 300 ), comprising:

a light guide ( 302 ) including a proximal end ( 510 ) configured to receive light from at least one light emitting diode ( 590 ), the proximal end ( 510 ) forming the received light into an internal beam inside the light guide ( 302 ),

the light guide ( 302 ) including a distal end ( 520 ), the distal end ( 520 ) having a peripheral portion ( 522 ) thereon;

the light guide ( 302 ) having a longitudinal axis (A) extending from the proximal end ( 510 ) to the distal end ( 520 ),

the light guide ( 302 ) including a lateral side ( 530 ) extending from a location adjacent the peripheral portion ( 522 ) of the distal end ( 520 ) to a location adjacent the proximal end ( 510 ),

wherein the lateral side ( 530 ) of the light guide ( 302 ) has a first region ( 550 ), a second region ( 560 ), a third region ( 570 ), and a fourth region ( 580 ), the first, second, third, and fourth regions extending successively from the proximal end ( 510 ) to the distal end ( 520 );

wherein in a cross-section that includes the longitudinal axis (A), the first region ( 550 ) is concave, the second region ( 560 ) is convex, the fourth region ( 580 ) is concave, and the third region ( 570 ) includes a smooth and continuous transition between the second region ( 560 ) and the fourth region ( 580 );

wherein in a cross-section that includes the longitudinal axis (A), the proximal end ( 510 ) of the light guide ( 302 ) has a concave portion ( 514 ) surrounded by a convex peripheral portion ( 516 ); and

wherein, in a cross-section that includes the longitudinal axis (A), at least a portion of the convex peripheral portion ( 516 ) and a portion of the concave first region ( 550 ) are at the same longitudinal location along the longitudinal axis (A).

2. The lamp ( 300 ) of claim 1 , wherein in the cross-section that includes the longitudinal axis (A), the third region ( 570 ) of the lateral side ( 530 ) comprises an inflection point between the convex second region ( 560 ) and the concave fourth region ( 580 ).

3. The lamp ( 300 ) of claim 1 , wherein at least a portion of the fourth region ( 580 ) and a portion of the distal end ( 520 ) are at the same longitudinal location along the longitudinal axis (A).

4. The lamp ( 300 ) of claim 1 , wherein a first portion ( 600 ) of the internal beam:

extends directly from the proximal end ( 510 ) of the light guide ( 302 ) to the first region ( 550 ) of the lateral side ( 530 ) of the light guide ( 302 ); and

exits the light guide ( 302 ) by transmitting through the first region ( 550 ).

5. The lamp ( 300 ) of claim 1 , wherein a second portion ( 700 ) of the internal beam:

extends directly from the proximal end ( 510 ) of the light guide ( 302 ) to the second region ( 560 ) of the lateral side ( 530 ) of the light guide ( 302 );

reflects via total internal reflection off the second region ( 560 );

crosses the longitudinal axis (A) of the light guide ( 302 );

strikes the peripheral portion ( 522 ) of the distal end ( 520 ) of the light guide ( 302 );

reflects, in part, from the peripheral portion ( 522 );

strikes the fourth region ( 580 ) of the lateral side ( 530 ) of the light guide ( 302 ); and

exits the light guide ( 302 ) by transmitting through the fourth region ( 580 ).

6. The lamp ( 300 ) of claim 1 , wherein a third portion ( 800 ) of the internal beam:

extends directly from the proximal end ( 510 ) of the light guide ( 302 ) to the third region ( 570 ) of the lateral side ( 530 ) of the light guide ( 302 );

reflects via total internal reflection from the third region ( 570 );

strikes the peripheral portion ( 522 ) of the distal end ( 520 ) of the light guide ( 302 ); and

exits the light guide ( 302 ) by transmitting, in part, through the peripheral portion ( 522 ).

7. The lamp ( 300 ) of claim 1 , wherein a fourth portion ( 900 ) of the internal beam:

extends directly from the proximal end ( 510 ) of the light guide ( 302 ) to the peripheral portion ( 522 ) of the distal end ( 520 ) of the light guide ( 302 );

reflects, in part, from the peripheral portion ( 522 );

strikes the fourth region ( 580 ) of the lateral side ( 530 ) of the light guide ( 302 ); and

exits the light guide ( 302 ) by transmitting through the fourth region ( 580 ).

8. The lamp ( 300 ) of claim 1 , wherein a fifth portion ( 1000 ) of the internal beam:

extends directly from the proximal end ( 510 ) of the light guide ( 302 ) to a central portion ( 524 ) of the distal end ( 520 ) of the light guide ( 302 ); and

exits the light guide ( 302 ) by transmitting through the central portion ( 524 ).

9. The lamp ( 300 ) of claim 1 , wherein in a cross-section that includes the longitudinal axis (A), the peripheral portion ( 522 ) of the distal end ( 520 ) of the light guide ( 302 ) is convex.

10. The lamp ( 300 ) of claim 1 , wherein the concave portion ( 514 ) includes a flat portion ( 512 ) surrounding the longitudinal axis (A).

11. The lamp ( 300 ) of claim 1 , wherein at least a location ( 592 ) on the convex peripheral portion ( 516 ) of the proximal end ( 510 ) of the light guide ( 302 ) is parallel to at least a location ( 594 ) on the first region ( 550 ) of the lateral side ( 530 ) of the light guide ( 302 ).

12. The lamp ( 300 ) of claim 1 , wherein the light guide ( 302 ) is rotationally symmetric about the longitudinal axis (A).

13. The lamp ( 300 ) of claim 1 , further comprising a housing ( 304 ) including a transparent portion ( 306 ), wherein the light guide ( 302 ) is disposed within the transparent portion ( 306 ) of the housing ( 304 ).

14. The lamp ( 300 ) of claim 1 , further comprising the at least one light emitting diode ( 590 ); wherein the at least one light emitting diode ( 590 ) comprises a plurality of light emitting diodes arranged circumferentially around the longitudinal axis (A) and spaced away from the longitudinal axis (A).

15. The lamp ( 300 ) of claim 1 , wherein the distal end ( 520 ) of the light guide ( 302 ) and the lateral side ( 530 ) of the light guide ( 302 ) are devoid of thin-film coatings.

16. The lamp ( 300 ) of claim 1 , wherein the peripheral portion ( 522 ) of the distal end ( 520 ) of the light guide ( 302 ) is frosted.

17. The lamp ( 300 ) of claim 1 , wherein in the cross-section that includes the longitudinal axis (A), the lateral side ( 530 ) varies smoothly and continuously between convex and concave regions.

18. The lamp ( 300 ) of claim 1 , wherein in the cross-section that includes the longitudinal axis (A), the lateral side ( 530 ) includes only a single convex region.

19. A lamp ( 300 ), comprising:

a light guide ( 302 ) including a proximal end ( 510 ) configured to receive light from at least one light emitting diode ( 590 ), the proximal end ( 510 ) forming the received light into an internal beam inside the light guide ( 302 ),

the light guide ( 302 ) including a distal end ( 520 ), the distal end ( 520 ) having a peripheral portion ( 522 ) thereon;

the light guide ( 302 ) having a longitudinal axis (A) extending from the proximal end ( 510 ) to the distal end ( 520 ),

the light guide ( 302 ) including a lateral side ( 530 ) extending from a location adjacent the peripheral portion ( 522 ) of the distal end ( 520 ) to a location adjacent the proximal end ( 510 ),

wherein the lateral side ( 530 ) of the light guide ( 302 ) has a first region ( 550 ), a second region ( 560 ), a third region ( 570 ), and a fourth region ( 580 ), the first, second, third, and fourth regions extending successively from the proximal end ( 510 ) to the distal end ( 520 );

wherein in a cross-section that includes the longitudinal axis (A), the first region ( 550 ) is concave, the second region ( 560 ) is convex, the fourth region ( 580 ) is concave, and the third region ( 570 ) includes a smooth and continuous transition between the second region ( 560 ) and the fourth region ( 580 ); and

wherein in a cross-section that includes the longitudinal axis (A), the proximal end ( 510 ) of the light guide ( 302 ) has a concave portion ( 514 ) surrounded by a convex peripheral portion ( 516 ).

20. The lamp ( 300 ) of claim 19 , wherein at least a location ( 592 ) on the convex peripheral portion ( 516 ) of the proximal end ( 510 ) of the light guide ( 302 ) is parallel to at least a location ( 594 ) on the first region ( 550 ) of the lateral side ( 530 ) of the light guide ( 302 ).