Collimating lens structures
View Patent ↗An optic element receives an input light beam with a first beam angle and an axis. The optic element includes a first surface that receives the input light beam and generates an expanded light beam with a second beam angle that is greater than or equal to the first beam angle. The optic element includes a second surface that receives the expanded light beam and generates an output light beam that is either substantially collimated or near collimated. The output light beam is tilted a predetermined degrees with respect to the axis of the input light beam.
1. An optic element, comprising:
a first surface comprising a sphere, the first surface configured to receive an input light beam at a first off-axis angle a, from a light source located at a predetermined distance L from the center of curvature of the sphere, and generate therefrom, an expanded light beam, wherein the predetermined distance L is equal to a product of the radius Rs of the sphere and a real number g that is selected from a range of values;
a second surface configured to receive the expanded light beam at a second off axis angle b with reference to a central axis of the expanded light beam, and generate therefrom an output light beam.
2. The optic element of claim 1 wherein at least one of the first surface and the second surface provides a tilting of the output light beam with respect to a central axis of the input light beam.
3. The optic element of claim 2 wherein the first surface provides about 50% of the tilting; and wherein the second surface provides about 50% of the tilting.
4. The optic element of claim 1 wherein the second surface is configured to generate a substantially collimated output light beam.
5. The optic element of claim 1 wherein the second surface is an ellipsoid surface.
6. The optic element of claim 1 wherein the output beam includes one of slightly converging rays and slightly diverging rays.
7. The optic element of claim 1 wherein the output light beam comprises collimated rays.
8. The optic element of claim 1 wherein the optic element is manufactured from one of glass and plastic.
9. The optical navigation device of claim 1 , wherein the shape of the first surface is selected to locate a first virtual source at a location away from the light source.
10. The optical navigation device of claim 9 , wherein the second surface is an ellipsoid having a polar radius Rp that is selected to locate a second virtual source at a distance M from the center of curvature at the pole of the ellipsoid, wherein M is equal to a product of the polar radius Rp and a real number h that is selected from a range of values.
11. The optical navigation device of claim 9 , wherein at least one of the first and second surfaces is configured to provide a tilting of the output light beam with respect to the central axis of the expanded light beam, wherein the optic element is configured to provide a pre-allocated amount of optical tilting in each of the two surfaces.
12. The optical navigation device of claim 1 , wherein the first off-axis angle a is in a range between about 5 degrees and about 45 degrees.
13. The optical navigation device of claim 1 , wherein the input light beam is directed upon the first surface at a first off-axis angle a that is in a range between about 10 degrees and about 35 degrees.
14. The optical navigation device of claim 1 , wherein g ranges from 1 to 2.5.
15. The optical navigation device of claim 1 , wherein the off-axis angle b ranges from about 2 degrees to about 30 degrees.
16. An optical navigation device comprising:
a light source having a central axis, the light source configured for generating a light beam; and
an optic element that includes a first surface comprising a spherical portion, the spherical portion having an axis that is parallel to the central axis of the light source for receiving the input light beam at an offset position on the first surface, and generating therefrom, an expanded light beam.
17. The optical navigation device of claim 16 , wherein the optic element further comprises a second surface configured for receiving the expanded light beam at an off-axis angle b with reference to a central axis of the expanded light beam, and generate therefrom, an output light beam.
18. The optical navigation device of claim 17 , wherein the first surface bends the light beam by M degrees relative to the central axis of the light source, and the second surface bends the light beam by N degrees relative to an axis of the expanded and once bent light beam.
19. A method for optically expanding, collimating, and bending a light beam comprising:
receiving in a spherical portion of a first surface of an optic element, a light beam at a first off-axis angle, the first off axis angle being an angle between a center axis of the spherical portion and a central axis of the received light beam;
using the first surface of the optic element for expanding the light beam to a second beam angle and bending the light beam to generate an expanded and once bent light beam; and
using a second surface of the optic element for collimating and bending the expanded and once bent light beam to generate a substantially collimated, twice-bent light beam.
20. The method of claim 19 wherein the first surface bends the light beam by M degrees relative to the central axis of the received light beam, and the second surface bends the light beam by N degrees relative to an axis of the expanded and once bent light beam.