Adjustable beam illuminator
An adjustable beam illuminator may provide a beam of light with an output cone angle that is adjustable (e.g., continuously adjustable) from small output angles (substantially collimated beam, “spot” mode) to larger output angles providing “flood” illumination. The illuminator may emit infrared light, for example.
1. An adjustable beam illuminator comprising:
a light emitting diode having a cross-sectional shape;
an aperture formed in a surface and having a cross-sectional shape different from that of the light emitting diode,
wherein the aperture transmits a central portion of a beam of light emitted by the light emitting diode, and outer portions of the beam from the light emitting diode are blocked;
an aspheric collecting lens mounted on the surface in which the aperture is formed, the aspheric collecting lens having a numerical aperture greater than or equal to about 0.5, and positioned to image the light emitting diode through the aperture to produce a beam of collected light having a cross-sectional shape approximately the same as that of the light emitting diode, the aspheric collecting lens positioned a distance from the light emitting diode that is equal to the focal length of the side of the aspheric collecting lens that faces the light emitting diode, wherein the aspheric collecting lens is larger than the aperture; and
a collimating lens adjustably positioned along an optical axis of the illuminator, the position of the collimating lens adjustable between a first position along the optical axis from which the collimating lens provides from the collected beam of light a substantially collimated output beam of light having a cross-sectional shape approximately the same as that of the aperture and a second position along the optical axis from which the collimating lens provides from the collected beam of light a diverging flood illumination beam of light also having a cross-sectional shape approximately the same as that of the aperture.
2. The adjustable beam illuminator of claim 1 , wherein the light emitting diode emits infrared light.
3. The adjustable beam illuminator of claim 1 , wherein the aspheric collecting lens has a numerical aperture greater than or equal to about 0.8.
4. The adjustable beam illuminator of claim 1 , wherein the aspheric collecting lens is mounted coaxially with the aperture on the surface in which the aperture is formed.
5. The adjustable beam illuminator of claim 1 , wherein the first position of the collimating lens is farther from the aperture than is the second position of the collimating lens.
6. The adjustable beam illuminator of claim 1 , wherein the position of the collimating lens is continuously adjustable between the first position and the second position.
7. The adjustable beam illuminator of claim 1 , wherein the substantially collimated output beam provided when the collimating lens is in the first position has a cone angle less than or equal to about 2 degrees, and the diverging flood illumination beam provided when the collimating lens is in the second position has a cone angle greater than or equal to about 30 degrees.
8. The adjustable beam illuminator of claim 1 , wherein the power in the diverging flood illumination output beam provided when the collimating lens is positioned in the second position is greater than the power in the substantially collimated output beam provided when the collimating lens is in the first position.
9. The adjustable beam illuminator of claim 1 , wherein:
the light emitting diode is an infrared light emitting diode;
the position of the collimating lens is continuously adjustable between the first position and the second position; and
the first position of the collimating lens is farther from the aperture than is the second position of the collimating lens.
10. The adjustable beam illuminator of claim 9 , wherein the power in the diverging flood illumination output beam provided when the collimating lens is positioned in the second position is greater than the power in the substantially collimated output beam provided when the collimating lens is in the first position.
11. The adjustable beam illuminator of claim 9 , wherein the substantially collimated output beam provided when the collimating lens is in the first position has a cone angle less than or equal to about 2 degrees, and the diverging flood illumination beam provided when the collimating lens is in the second position has a cone angle greater than or equal to about 30 degrees.
12. The adjustable beam illuminator of claim 11 , wherein the power in the diverging flood illumination output beam provided when the collimating lens is positioned in the second position is greater than the power in the substantially collimated output beam provided when the collimating lens is in the first position.
13. The adjustable beam illuminator of claim 1 , arranged in a housing configured for mounting to a firearm.
14. The adjustable beam illuminator of claim 13 , sharing the housing with an aiming laser.
15. The adjustable beam illuminator of claim 9 , arranged in a housing configured for mounting to a firearm.
16. The adjustable beam illuminator of claim 15 , sharing the housing with an aiming laser.
17. The adjustable beam illuminator of claim 9 , wherein the aspheric collecting lens is mounted coaxially with the aperture on the surface in which the aperture is formed.
18. The adjustable beam illuminator of claim 11 , wherein the aspheric collecting lens is mounted coaxially with the aperture on the surface in which the aperture is formed.