Wide angle based indoor lighting lamp

1. An illumination structure comprising: a light-emitting diode (LED) device on a substrate; a lens secured on the substrate and over the LED device, and wherein a gap exists between the LED device and the lens; and a diffuser cap secured on the substrate and covering the lens, wherein the lens and diffuser cap are designed and configured to redistribute emitting light from the LED device for wide angle illumination; and wherein: the lens includes an inner surface and an outer surface; the inner surface includes a first side portion and a first top portion; the outer surface includes a second side portion and a second top portion, the second side portion extending from a bottom surface and having a concave curved cross-sectional profile configured in a manner such that a bottom of the second side portion protrudes further out from a center of the lens than a top of the second side portion.

2. The illumination structure of claim 1 , wherein

the first side portion, the first top portion, the second side portion, and the second top portion are designed and configured to redistribute light emitted from the LED device to a solid angle more than 2π steradian.

3. The illumination structure of claim 2 , wherein the first side portion, the first top portion, the second side portion, and the second top portion are designed and configured such that during an operation of the illumination structure the emitted light includes:

a first light beam passing through the first top portion and the second top portion that is distributed within a first solid angle between 0 steradian and about 2π*[1−cos(π/4)] steradian;

a second light beam passing through the first side portion and the second side portion that is distributed within a second solid angle between about 2π*[1−cos(π/4)] steradian and about 2π*[1−cos(100π/180)] steradian; and

a third light beam passing through the first top portion, reflecting from the second top portion, and passing through the second side portion that is distributed within a third solid angle between about 2π*[1−cos(100π/180)] steradian and 4π steradian.

4. The illumination structure of claim 2 , wherein the second top portion has a concave recess.

5. The illumination structure of claim 4 , wherein

the second top portion includes a center and a rim surrounding the center;

the second top portion is spaced away from the substrate along a first direction, defining a height H from the rim of the second top portion to a top surface of the substrate along the first direction;

the second top portion spans from the center to the rim along a second direction perpendicular to the first direction, defining a first radius r;

the concave recess includes a recess depth d defined as a distance from the rim to the center along the first direction; and

a first ratio d/H ranges between about 0.5 and about 0.8.

6. The illumination structure of claim 5 , wherein

the second side surface defines a round area on the substrate and the round area has a second radius R along the second direction; and

a second ratio r/R ranges between about 0.3 and about 1.0.

7. The illumination structure of claim 6 , wherein

the first top portion is spaced away from the substrate along the first direction, defining a height h to the top surface of the substrate; and

a third ratio h/H ranges between about 0.1 and about 0.4.

8. The illumination structure of claim 1 , further comprising a second lens covering the first lens and configured inside the diffuser cap.

9. The illumination structure of claim 1 , wherein the substrate includes a mechanical base.

10. The illumination structure of claim 9 , wherein the mechanical base includes a thermal conductive material and is designed as a heat sink.

11. The illumination structure of claim 9 , wherein

the mechanical base includes a first portion adjacent the LED device and a second portion remote from the LED device;

the first portion and the second portion are configured along a first direction;

the first portion has a first dimension along a second direction perpendicular to the first direction;

the second portion has a second dimension along the second direction; and

the second dimension is greater than the first dimension.

12. The illumination structure of claim 1 , further includes a heat spreading circuit board electrically coupled with the LED device; and configured between the LED device and the substrate.

13. The illumination structure of claim 1 , wherein the second side portion has a concave shape.

14. An illumination structure comprising: a light-emitting diode (LED) device disposed over a substrate; and a lens disposed over the substrate and over the LED device; wherein: the lens includes an inner surface facing toward the LED device and an outer surface facing away from the LED device; the outer surface includes a curved top surface and a concave side surface; concave side surface extending from a bottom surface of said lens and being shaped such that the lens has a larger radius at a bottom of the lens than at a top of the lens; and the curved top surface has a vertex.

15. The illumination structure of claim 14 , wherein the curved top and side surfaces are each configured to resemble a portion of a hemisphere or a portion of a semi-ellipse.

16. The illumination structure of claim 14 , further comprising a diffuser cap disposed over the substrate and housing the LED device and the lens within.

17. The illumination structure of claim 14 , wherein the lens includes a transparent material selected from the group consisting of polycarbonate (PC) and poly methyl methacrylate (PMMA).

18. The illumination structure of claim 14 , wherein the LED device includes a plurality of LED chips.

19. The illumination structure of claim 14 , wherein the lens is shaped as a batwing structure.

20. The illumination structure of claim 14 , wherein:

the top surface defines a concave recess, and wherein a lowest point of the recess is the vertex and is centered around the LED device; and

the side surface has a concave shape in a cross-sectional view.

21. An illumination structure, comprising: a light-emitting diode (LED) device disposed over a substrate, the LED device including one or more LED chips; a batwing-shaped lens disposed over the substrate and over the LED device, wherein the one or more LED chips are each spaced apart from the batwing-shaped lens; and a diffuser cap disposed over the substrate and housing the LED device and batwing-shaped lens therein; wherein: an upper surface of the batwing-shaped lens defines a concave recess, that includes a vertex, and wherein the vertex defines a lowest point of the upper surface and is being aligned with a center of the LED device; a side surface extending from a bottom surface of the batwing-shaped lens has a concave and non-flat cross-sectional profile; and a first radius of a bottom portion of the batwing-shaped lens is greater than a second radius of a top portion of the batwing-shaped lens.

22. The illumination structure of claim 21 , wherein the batwing-shaped lens includes a transparent material selected from the group consisting of polycarbonate (PC) and poly methyl methacrylate (PMMA).