Lens with elongated radiation pattern
An elongated lens ( 300 ) is formed with a trough ( 310 ) along the long axis on the light emitting surface of the lens. The elongated lens ( 300 ) may include a curved wall ( 325 ) about its perimeter, and a smooth transition ( 317 ) between the curved wall ( 325 ) and the trough ( 310 ). The trough ( 310 ) may include a concave shape along both the long axis and the short axis, although the radius of curvature of the concave shape may differ between the long and short axes. The eccentricity of the illumination pattern may be controlled by the size of the trough ( 310 ) and these radii of curvature.
1. A light emitting device comprising:
a light emitting element; and
an elongated lens having a short axis, a long axis, and an upper surface through which a substantial majority of the light from the light emitting device is emitted;
the upper surface of the lens being smooth and continuous and including a trough that extends along the long axis, and
the perimeter of the lens being one of substantially oval or substantially elliptical.
2. The device of claim 1 , wherein the trough is symmetric about at least one of the short and the long axis with respect to an optical axis of the light emitting element.
3. The device of claim 1 , wherein the upper surface includes a surface of a curved wall of the light emitting device.
4. The device of claim 3 , wherein a smooth transition joins the trough to the curved wall.
5. The device of claim 3 , wherein at least a portion of the curved wall is reflective.
6. The device of claim 1 , wherein a lower surface of the trough has a curvature along the short axis that differs from a curvature along the long axis.
7. The device of claim 1 , wherein a perimeter of the trough is substantially oval.
8. A vehicle lamp comprising:
a light emitting device; and
a lens comprising:
an elongated shape, the lens having a short axis and a long axis;
an upper surface through which a substantial majority of light exits the lens when a light emitting element is situated at or below a base of the lens;
the upper surface being smooth and continuous and including a trough that extends along at least one of the short and the long axis, and
the perimeter of the lens being one of substantially oval or substantially elliptical.
9. A light emitting device comprising:
a light emitting element; and
an elongated lens having a short axis, a long axis, and an upper surface through which a substantial majority of the light from the light emitting device is emitted;
the upper surface of the lens being smooth and continuous and including a trough that is substantially concave along both the long axis and the short axis.
10. The device of claim 9 , wherein the trough is symmetric about at least one of the short and the long axis with respect to an optical axis of the light emitting element.
11. The device of claim 9 , wherein the upper surface includes a surface of a curved wall of the light emitting device.
12. The device of claim 9 , wherein a smooth transition joins the trough to the curved wall.
13. The device of claim 9 , wherein at least a portion of the curved wall is reflective.
14. The device of claim 9 , wherein a lower surface of the trough has a curvature along the short axis that differs from a curvature along the long axis.
15. The device of claim 9 , wherein a perimeter of the lens is substantially oval.
16. A light emitting device comprising:
a light emitting element; and
an elongated lens having a short axis, a long axis, and an upper surface through which a substantial majority of the light from the light emitting device is emitted;
the upper surface of the lens including a trough that extends along the long axis, a lower surface of the trough being substantially flat near the center of the trough.