LED traffic signal and optical element therefor

1. A lighting device comprising:

a housing having an open end;

a refractive optical element closing the open end of the housing, the optical element comprising a converging outer surface and a diverging inner surface; and

a light source cooperating with the optical element, wherein the light source is disposed proximate the focal point of the refractive optical element.

2. The lighting device according to claim 1 , wherein the optical element comprises an inner surface having a reference plane normal to the trajectory of the incoming light rays.

3. The lighting device according to claim 2 , wherein the optical element comprises a collimating lens, the inner surface being configured to be planar and normal to light rays emanating from the light source and the outer surface being configured to redirect light rays to provide a generally collimated light beam pattern.

4. The lighting device according to claim 1 , further comprising a support carrying at least one LED.

5. The lighting device according to claim 3 , wherein the housing has a geometrical axis and the support is spaced toward the open end from the focal point.

6. A lighting device comprising:

a housing having an open end and a geometrical axis;

at least one light source disposed along an optical axis;

an outer optical element having a focal point and closing the open end of the housing, the optical element comprising a converging outer surface and a diverging inner surface that cooperates with the light coming from the inner optical element; and

an inner optical element between the light source and the outer optical element, the inner optical element redirecting light from a light source that is offset from the focal point toward the outer optical element.

7. The lighting device according to claim 6 , wherein the outer and inner optical elements are rotationally symmetrical about the geometrical axis.

8. The lighting device according to claim 6 , wherein the inner surface of the outer optical element is facetted and the outer surface of the outer optical element is smooth.

9. The lighting device according to claim 6 , wherein the light source includes a first and second light source, the first light source being disposed closer to the inner optical element than the second light source.

10. The lighting device according to claim 6 , wherein the outer optical element is configured to cooperate with a second light source to provide a generally collimated light beam pattern.

11. The lighting device according to claim 6 , further comprising a support for a plurality of LEDs.

12. A lighting device comprising:

a housing having an open end; and

at least two converging lenses, wherein one converging lens is positioned to collect most of the light from a light source and another converging lens is positioned to close the open end of the signal lamp and distribute the light for a given specification.

13. The lighting device according to claim 12 , further comprising at least one light source disposed along an optical axis and wherein the housing has a geometrical axis.

14. The lighting device according to claim 12 , further comprising a support for a plurality of LEDs.

15. A lighting device comprising:

a housing having an open end;

a light source; and

a converging lens comprising a curved entry face, a total internal reflection face and an exit face, wherein the curved entry face is configured to converge the light from the light source toward the center of the total internal reflection face.

16. The lighting device according to claim 15 , further comprising a support for a plurality of LEDs.

17. The lighting device according to claim 15 , wherein the light source is disposed along an optical axis and wherein the housing has a geometrical axis.