LED illuminator with improved beam quality

An improved illuminator with an adjustable beam pattern to be worn by medical and dental professionals includes a housing, a light-emitting diode (LED) disposed in the housing outputting light through a distal opening in the housing, an achromatic doublet lens mounted in the opening in the housing, and a singlet lens disposed between the LED and the achromatic lens. The distance between the singlet lens and the doublet lens may be adjustable, and/or distance between the LED and the singlet lens may be adjustable, through a threaded connections, for example. In the preferred embodiment, the achromatic doublet lens, the singlet lens, or both the singlet and the doublet lens have a planar surface.

FIELD OF THE INVENTION

This invention relates generally to illuminators of the type worn by medical and dental professionals and, in particular, to an LED illuminator with multiple optical elements to improve beam quality

BACKGROUND OF THE INVENTION

The light generated by existing light-emitting diode (LED) illuminators is quite poor. Current illuminators of this kind use reflecting optical elements or singlet or multiple lenses with reflecting optical elements. An example is shown in U.S. Pat. No. 3,745,993 entitled “Surgical Headlight.” Although this design discloses an achromatic lens, the light delivered to it from an optical fiber is reflected off of a mirror. As such, this and other existing configurations exhibit poor light uniformity and/or unacceptable color separation at the edge of beam.

SUMMARY OF INVENTION

This invention improves upon existing designs by providing an illuminator with an adjustable beam pattern to be worn by medical and dental professionals. The preferred embodiments include a housing, a light-emitting diode (LED) disposed in the housing outputting light through a distal opening in the housing, an achromatic doublet lens mounted in the opening in the housing, and a singlet lens disposed between the LED and the achromatic lens.

The distance between the singlet lens and the doublet lens may be adjustable, and/or distance between the LED and the singlet lens may be adjustable, through a threaded connections, for example. In the preferred embodiment, the achromatic doublet lens, the singlet lens, or both the singlet and the doublet lens have a planar surface.

DETAILED DESCRIPTION OF THE INVENTION

This invention resides in an LED illuminator with multiple optical elements to improve beam quality. All embodiments include a housing with an LED source, a singlet lens supported in front of the LED, and an achromatic doublet lens in position where the light exits the housing. An attachment mechanism is coupled to the housing, enabling the illuminator to be worn as a headlamp.

One embodiment, shown inFIG. 1, uses a singlet lens104and an achromatic doublet lens106made with one positive and one negative lens elements108,110. This and the other embodiments disclosed herein are based upon a high-intensity white-emitting LED100including an integral lens102, which may be spherical.

One or both distances A, B inFIG. 1can be either fixed or adjustable for beam pattern or different applications. For typical headlamp applications, A may be on the order of 6 mm, adjustable between 4 to 11 mm, while B may be on the order of 4 mm, adjustable between 2 to 6 mm or thereabouts. The diameter of the singlet104may be in the range of 7 to 10 mm, whereas the achromatic doublet lens106will be on the order of 17 to 20 mm, again for typical headlamp applications. The radius of the LED lens may be 2.5 mm +/− 0.5 mm.

FIG. 3shows a suitable housing for the preferred optical assembly. Doublet108,110, is disposed in a housing302; singlet104is disposed in housing304, and LED102is mounted within housing306. The housings are coupled via threaded connections330,340, with set screws332,342and/or an adhesive being used to fix the relative positions. If one or both distances are permanently fixed, one or both of the threaded connections330,340may be eliminated, simplifying the housing overall.

The base housing306is preferably coupled to a clip-on type connector320through hinge310. The invention is not limited in this regard insofar as other attachment mechanisms may be used. Any materials such as plastic, metal (i.e., aluminum) may be used for the housing pieces. Heat vents or sinks (not shown) may also be provided. The cord for the LED is depicted at322.

FIG. 4is a cross section of a preferred embodiment of the invention, andFIG. 5is a ray-tracing diagram of the embodiment ofFIG. 4. In this configuration, one or both of the singlet lens402and doublet lens404includes a planar surface (i.e., surfaces403,405), resulting in a configuration which is more compact that the embodiment ofFIGS. 1,2.FIG. 4provides typical lens diameters, dimensions and weights for a medical/dental illuminator with the understanding that these values represent one combination of many. The optical elements ofFIGS. 4,5would be mounted in a housing comparable to that shown inFIG. 3. An aperture stop is optionally provided to beam pattern with a desired shape such as round.