Patent Number: 047926929
Section: claims

1. A dental irradiation apparatus comprising a lamp for producing a convergent beam of radiation having an angle of convergence approximately 30.degree. or less with respect to the optical axis defined by said lamp, and  an optical waveguide having an entrance surface disposed in said beam and an exit surface adapted to be oriented with respect to a location to be irradiated, the waveguide being conically shaped over a substantial part of its length with a diameter decreasing from said entrance surface to said exit surface. 2. The apparatus of claim 1, wherein the material of the waveguide has a refractive index ratio with respect to the environment of greater than approximately 1.3. 3. The apparatus of claim 2, wherein the refractive index ratio is approximately .sqroot.2. 4. The apparatus of clim 1, wherein the ratio of the diameter of the exit surface to that of the entrance surface of said waveguide is between about 0.5 and about 0.2. 5. The apparatus of claim 4, wherein the said ratio is about 0.3. 6. The apparatus of claim 1, wherein the entrance surface has a diameter of approximately 10 mm, the exit surface has a diameter of approximately 3 mm, and the length of the waveguide is approximately 100 mm. 7. The apparatus of claim 1, wherein a portion of the waveguide near the exit surface is bent about an angle of approximately 60.degree. to 90.degree.. 8. The apparatus of claim 7, wherein said angle is approximately 75.degree.. 9. The apparatus of claim 7, wherein the diameter of the bent portion is substantially uniform. 10. The apparatus of claim 1, wherein the exit surface is rounded. 11. The apparatus of claim 1, wherein a portion of the waveguide immediately adjacent the exit surface has a cone angle greater than that of the other part of the waveguide, the diameter decreasing within adjacent portion to such an extent that radiation exits through the conical peripheral surface of said portion at a distance of up to 20 mm from said exit surface.