Edge coupled light collimation for backlight
A backlight apparatus can include a lens to receive light and generate light with a collimated batwing configuration. The lens can include a receiving surface and an opposing transmission surface. The lens can be symmetric about a plane of symmetry. The transmission surface can include an angle of curvature that increases closer to the plane of symmetry.
1. A backlight apparatus, comprising:
a backplate;
a light emitting element located within the backplate and configured to emit visible light;
a lens located within the backplate and configured to angularly redirect the visible light into a batwing configuration of first and second collimated light beams, the lens including a parabolic-shaped receiving surface facing the light emitting element and a transmission surface opposing the receiving surface, the transmission surface including an angle of curvature that increases closer to a plane of symmetry of the lens; and
a light guide panel configured to distribute light from the first and second collimated light beams to a surface of the light guide panel facing a display device.
2. The backlight apparatus of claim 1 , wherein:
an angle of a center axis of the first collimated light beam is greater than 45 degrees from the plane of symmetry of the lens, and
an angle of a center axis of the second collimated light beam is greater than negative 45 degrees from the plane of symmetry of the lens.
3. The backlight apparatus of claim 1 , wherein:
the lens is situated between the light emitting element and the light guide panel, and
the light emitting element is situated between the backplate and the lens.
4. The backlight apparatus of claim 1 , wherein the lens further includes generally planar feet opposing the transmission surface and from which the receiving surface extends.
5. The backlight apparatus of claim 1 , wherein a first perimeter of a surface of the lens facing the light emitting element and opposing the transmission surface is smaller than a second perimeter of the transmission surface.
6. The backlight apparatus of claim 5 , wherein the first perimeter is generally rectangular, and the second perimeter includes first and second opposing curved edges with an angle of curvature that increases closer to the plane of symmetry of the lens.
7. The backlight apparatus of claim 6 , wherein the second perimeter includes generally linear opposing edges extending between the first and second opposing curved edges.
8. The backlight apparatus of claim 7 , wherein the lens includes first and second sides extending between respective generally linear edges and respective feet.
9. The backlight: apparatus of claim 8 , wherein the first and second sides tilt away from the respective feet as they extend towards the respective generally linear edges.
10. The backlight apparatus of claim 8 , wherein the lens includes opposing third and fourth sides extending between the first and second curved edges in a first dimension and a respective generally linear opposing edge of the generally linear opposing edges and a respective foot of the respective feet in a second dimension.
11. The backlight apparatus of claim 10 , wherein the third and fourth sides include concave edges facing the light emitting element and extending between the first and second curved edges, respectively, and the respective feet in a third dimension wherein the third and fourth sides tilt away from the respective feet as they extend towards the first and second curved edges.
12. The backlight apparatus of claim 11 , wherein the concave edges include an angle of curvature that increases closer to the respective feet.
13. A display device comprising:
a liquid crystal display;
a light emitting element configured to emit visible light;
a circuit board electrically and mechanically coupled to the light emitting element;
a lens configured to angularly redirect the visible light into a batwing configuration of first and second collimated light beams, the lens including a parabolic-shaped receiving surface facing the light emitting element and a transmission surface opposing the receiving surface, the transmission surface including an angle of curvature that increases closer to a plane of symmetry of the lens; and
a light guide panel configured to distribute light from the first and second light beams to a surface of the light guide panel facing the liquid crystal display.
14. The display device of claim 13 , wherein:
an angle of a center of the first collimated light beam is greater than 45 degrees from the plane of symmetry of the lens, and
an angle of the second collimated light beam is greater than negative 45 degrees from the plane of symmetry of the lens.
15. The display device of claim 13 , wherein:
the lens further includes feet opposing the transmission surface and from which the receiving surface extends;
a first perimeter of a surface of the lens facing the light emitting element and opposing the transmission surface is smaller than a second perimeter of the transmission surface, and the second perimeter includes first and second opposing curved edges with an angle of curvature that increases closer to the plane of symmetry of the lens.
16. The display device of claim 15 , wherein:
the lens includes first and second sides extending between respective generally linear edges and respective feet; and
the first and second sides tilt away from the respective feet towards the respective generally linear edges.
17. The display device of claim 16 wherein:
the lens includes opposing third and fourth sides extending between the first and second curved edges in a first dimension, respectively, and a respective generally linear opposing edge of the generally linear opposing edges and a respective foot of the respective feet in a second dimension; and
the third and fourth sides include concave edges facing the light emitting element and extending between the between the first and second curved edges, respectively, and respective feet in a third dimension, wherein the third and fourth sides tilt away from the respective feet as they extend towards the first and second curved edges.
18. The display device of claim 16 , wherein the concave edges include an angle of curvature that increases closer to the feet.
19. A method of forming a backlight apparatus, the method comprising:
obtaining a lens that includes a parabolic-shaped receiving surface and a transmission surface, the lens being symmetric about a plane of symmetry that bisects the transmission surface;
coupling the lens to a top of a housing that contains a light-emitting element therein such that the light emitting element faces an aperture in the top of the housing and a receiving surface of the lens the lens configured to angularly redirect light from the light-emitting element into a batwing configuration of first and second collimated light beams; and
electrically and mechanically coupling the light-emitting element to a circuit board.
20. The method of claim 19 , further comprising situating a light guide panel to receive light emitted by the lens and to distribute the light towards a display device.