|Número de publicación||US3704928 A|
|Tipo de publicación||Concesión|
|Fecha de publicación||5 Dic 1972|
|Fecha de presentación||9 Nov 1970|
|Fecha de prioridad||9 Nov 1970|
|Número de publicación||US 3704928 A, US 3704928A, US-A-3704928, US3704928 A, US3704928A|
|Inventores||Peter M Coombs, Ernest Davey, Conrad Edward Kowalski|
|Cesionario original||Sylvania Electric Prod|
|Exportar cita||BiBTeX, EndNote, RefMan|
|Citas de patentes (7), Otras citas (1), Citada por (34), Clasificaciones (19)|
|Enlaces externos: USPTO, Cesión de USPTO, Espacenet|
()R 3,70 ,92 SEARCH ROOM United States Patent V [151 3,704,928
Cmmbselal- SUBSTITUTE FOR MlSSING on Dec-$1972 [5 1 DENTAL LIGHT WITH DICHRQIC AND 1,279,638 9/1918 Blake ..240/41.a
INFRARED FILTERS OTHER PUBLICATIONS  Inventors: Peter M. Coombs, Newton, N.H.;
Ernest Davey, Lynn; Com-ad Degenkolb, et al., Dichroic Safeguards, Journal of ward Kowabki, Marblehead, both the S.M.P.T.E, V01. 76, No. 1,.1an. 1967, pp. 15-17 of Mass. Pr'ma Exam Dav'd Schonber  Assrgnee: Sylvnnla Electric Products, Inc. L- Kusmegr  Filed: Nov. 9, 1970 Attorney-Norman J. O'Malley, Laurence Burns and [211 App]. No.: 87,792 Ryan  ABSTRACT  US. Cl. ..350/l, 240/41.15, 240/41.3, A fixture for denial illumination in which an elliptical 5i] i t Cl :;35822 reflector and light source is used with a light gate and  d 163 166 projection lens, these being set in an enclosing e 0 canister with the light emerging through the lens, an
350/316; 240/4115 413; 353,55 infrared filter in the path of the light rays to absorb unwanted heat radiation, and a dichroic filter on the  References Cited surface of the lens facing the reflector to correct the UNITED STATES PATENTS light-rendering index of the emitted light. Without any filter, neither infrared nor visible, the color rendering 3,371,202 2/1968 Moore et a1. ..240/41.3 index of the light from the cievice is 97 5 w the 2,798,943 7/1957 Pndeaux ..353/55 X infrared filter iS added, this drops to 0 but the 2,827,554 3/1958 Gunther et a1 ..350/316 X dition of the (chi-oic visih|e iight filter brings ihiS 3,113,033 12/1963 Hoxie et al. ..350/1 X back to 97 which is very good.
1,349,706 8/1920 Worcester ..240/41.3
2,338,901 1/1944 Chiti ..240/4l.3 l C1alrn,2 Drawing Flgures PAIENTEDuEc 5 m2 UNCOATED WAVELENGTH IN MILL IMICRONS 400 425 wozsitzwzdmk PETER M. COOMBS ERNEST DAVEY C. EDWARD KOWALSKI INVENTORS ATTORNEY DENTAL LIGHT WITH DICIIROIC AND INFRARED FILTERS BACKGROUND OF THE INVENTION I. Field oflnvention This invention relates to fixtures for dental illumination, and in particular to such fixtures which utilize a heat-absorbing filter to prevent excessive heating of the patients face by infrared radiation.
2. Brief Summary of Prior Art Dental fixtures have been developed using a light source at one focus of an ellipsoidal reflector, and at the other focus a gate having an opening defining the extent of the beam. These provide a high intensity of light on the patients face, but since the light source is an incandescent lamp, most of its radiated energy is infrared, which does not assist the dentist in seeing, but can undesirably heat up the face of the patient on which it falls. A filter plate is used in front of the lens, that is between the lens and the patient's face to absorb the infrared and produce a cooler light.
The usual infrared filters have a broad cutoff and also absorb visible light in some parts of the spectrum. The quality of the light emitted from the fixture without the filter is such that its color-rendering index is 97.5, which is considered excellent, but the addition of the filter drops this index to 88, which is undesirable, since the dentist needs to see the patients teeth in their natural colors.
The glass filters available for cutting off the far infrared are found to transmit more in the green and yellow than in the blue, and since the incandescent source is comparatively low in blue radiation, this means that the green light will predominate and give the light a greenish tinge which is undesirable.
BRIEF SUMMARY OF INVENTION It is here that our invention solves the problem by using an additional filter which cuts down on the green and has high transmission for the blue. The filter also cuts down on the yellow, orange and red somewhat, but since the source is rich in these colors anyway, this merely helps to give a balanced light. The color temperature is raised to an acceptable balance, and the color rendering index is brought back to 97.5. We have discovered that this filter can best be utilized by making it of the dichroic type, which can be coated onto some light-transmitting part of the device. The dichroic filter was tried at the light gate, but the high radiation density at that point destroyed the dichroic coating. A coating on the back of the infrared filter, that is, on the side nearest the lens, was found to give secondary reflections back onto the gate, which was transmitted into the illuminating pattern, which was undesirable. A third approach was tried by coating the external surface of the infrared filter, but this left the coating vunerable to abrasion when cleaned.
We have discovered that all these disadvantages can be overcome by having a dichroic coating on the lens surface which faces the source of light. In the optical system used, this was the spheric side of the lens, the other side being aspheric.
BRIEF SUMMARY OF DRAWINGS Other features, objects and advantages of the invention will be apparent from the following specification, taken in connection with the accompanying drawings in which:
FIG. 1 is a graph of transmittance against wavelength for the infrared filter and for the dichroie filter on the lens; and
FIG. 2 is a longitudinal section through the centerline of the fixture.
DESCRIPTION OF SPECIFIC EMBODIMENTS In FIG. I, the dotted curve shows the transmission of the infrared filter for visible light and is to be somewhat low in the blue (400-500 millimicrons), higher in the green and yellow (500-600 millimicrons), and low again in the red (600-750 millimicrons). This, in conjunction with the incandescent filament source, produces a somewhat greenish light.
The full-line curve shows the transmission of the diehroie filter, which is high in the blue, and low in the yellow and green, rising somewhat toward the red.
Although only the visible transmissions of the filters are shown, the transmission of the infrared filter drops to zero at about 900 millimicrons and continues there up to at least 2,700 millimicrons, which was the limit of the measuring equipment.
Referring to FIG. 2, a cross sectional view of the medical and dental fixture is shown. The major components comprise a main housing canister I0, an optical system I2 located within the canister and a flexible boot l4 affixed to the rear end of the canister. The boot 14 covers and holds the electrical connections for a lamp [6. The lamp, being one of the components of the optical system of the fixture, is positioned within an ellipsoidal-shaped reflector I8. The lamp and reflector produce an intense source whose light is directed through a rectangular opening 24 centrally located in a fixed light gate 20. A spacing rim 22 spaces the lamp and reflector from the light gate so that an optimum amount of light produced by the lamp 16 passes through the gate opening 24 and thence to an aspheric lens 26, and an exterior heat absorbing cover glass 32.
The lens 26 and heat absorbing cover glass 32 are spaced from one another and held by a circular bezel 30. This segment of the optical system produces a very sharply defined rectangular light pattern.
The optically clad glass rod 40 shown in FIG. 2 is made of a glass rod probe with optically polished ends and encased within a metal casing. One end of the rod 40 extends into the housing 10, and passes through the reflector and terminates just short of the envelope 51 of the lamp, and perpendicular to the axis of the filament 50. The other end of the rod 40 extends outwardly from the housing 10 and is connected to a flexible fiber optic conduit comprised ofa standard bundle of flexible glass fibers 44 in the shape of a conduit having an approximately circular cross section.
With this arrangement the rod 40 collects from the filament light which travels over the conduit 44 to emerge at the light exit end 48.
The lens surface facing the source of light, that is, the back surface 28 of the lens 26 is coated with a dichroic filter 9 which transmits more blue light than green, and
which also passes the red. The filter can be made in the usual manner with successive thin coats or layers of magnesium fluoride and zinc sulfide, each about onefourth wavelength thick, there being 9 coats of magnesium fluoride and 10 coats of zinc sulfide in all. The coatings can be applied by vacuum disposition in the usual manner.
What we claim is: l. A dental lighting fixture comprising: an optical system including an ellipsoidal reflector having a light source disposed at one focus thereof; a fixed light gate disposed in front of said optical system, said gate having a rectangular opening disposed at the other focus of said ellipsoidal reflector;
a lens disposed in front of said light gate, said lens having a spheric side facing said light gate, the other side of said lens being aspheric;
a dichroic coating disposed on said spheric side of said lens, said coating having higher transmission of blue light than of green, yellow, orange or red light; and
an infrared absorbing glass fllter disposed in front of said lens, the combination of said dichroic coating and said filter yielding light of high color rendering index.
i l I I!
|Patente citada||Fecha de presentación||Fecha de publicación||Solicitante||Título|
|US1279638 *||5 Jul 1917||24 Sep 1918||Hall Switch & Signal Co||Light-signal.|
|US1349706 *||26 Sep 1914||17 Ago 1920||Light-projecting lantern|
|US2338901 *||14 May 1940||11 Ene 1944||Chiti Aroldo||Vehicle lamp|
|US2798943 *||20 Oct 1955||9 Jul 1957||Gen Electric||Spotlight apparatus|
|US2827554 *||12 Oct 1954||18 Mar 1958||Gunther Franz||Operating table lamp|
|US3113033 *||16 May 1960||3 Dic 1963||Corning Glass Works||Light filter|
|US3371202 *||21 Jul 1966||27 Feb 1968||Wech Allyn Inc||Medical headlight|
|1||*||Degenkolb, et al., Dichroic Safeguards, Journal of the S.M.P.T.E, Vol. 76, No. 1, Jan. 1967, pp. 15 17|
|Patente citante||Fecha de presentación||Fecha de publicación||Solicitante||Título|
|US3930149 *||28 May 1974||30 Dic 1975||Sterndent Corp||Variable intensity dental light|
|US4151584 *||14 Mar 1977||24 Abr 1979||Electro Controls Inc.||Light-collecting reflector|
|US4195329 *||1 Dic 1977||25 Mar 1980||Les Produits Associes Lpa Sa||Diagnostic lamp, particularly for checking teeth|
|US4234247 *||30 Oct 1978||18 Nov 1980||Corning Glass Works||Method of making a reflector|
|US4240133 *||19 Abr 1978||16 Dic 1980||Gesellschaft fur Strahlen-und Umweltforschung mbH, Munchen||Quasimonochromatic light source|
|US4254455 *||21 Dic 1979||3 Mar 1981||Pelton & Crane Company||Reflector for dental, medical or the like lighting device|
|US4266535 *||12 Abr 1979||12 May 1981||Les Produits Associes Bpa Sa||Diagnostic lamp|
|US4292664 *||17 Ago 1978||29 Sep 1981||Clairol Incorporated||Dental plaque disclosing light and method|
|US4386292 *||2 Jul 1980||31 May 1983||Gte Products Corporation||Projection lamp comprising single ended arc discharge lamp and an interference filter|
|US4571665 *||11 Mar 1983||18 Feb 1986||Espe Fabrik Pharmazeutischer Praeparate Gmbh||Apparatus for treating dental materials|
|US4897772 *||23 Dic 1988||30 Ene 1990||G-C Dental Industrial Corp.||Dental astral lamp|
|US5003434 *||13 Jul 1990||26 Mar 1991||Den-Tal-Ez, Inc.||Miniature hand-held spot source of illumination|
|US5093769 *||4 Oct 1990||3 Mar 1992||Luntsford K Paul||Surgical lighting system|
|US5345371 *||5 Nov 1992||6 Sep 1994||Cunningham David W||Lighting fixture|
|US5446637 *||14 Jul 1994||29 Ago 1995||Cunningham; David W.||Lighting fixture|
|US5728994 *||7 Jun 1995||17 Mar 1998||Vari-Lite, Inc.||Laser ablation method for making a light pattern generator on a transparent substrate|
|US5959768 *||17 Sep 1996||28 Sep 1999||Vari-Lite, Inc.||Light pattern generator formed on a transparent substrate|
|US6369964||4 Sep 1998||9 Abr 2002||General Scientific Corporation||Optical filters for reducing eye strain, during surgery|
|US6890175||18 Dic 2002||10 May 2005||Ultradent Products, Inc.||Cooling system for hand-held curing light|
|US6940659||23 Dic 2002||6 Sep 2005||Ultradent Products, Inc.||Cone-shaped lens having increased forward light intensity and kits incorporating such lenses|
|US6994546||18 Dic 2002||7 Feb 2006||Ultradent Products, Inc.||Light curing device with detachable power supply|
|US7056116||26 Oct 2004||6 Jun 2006||Ultradent Products, Inc.||Heat sink for dental curing light comprising a plurality of different materials|
|US7074040||30 Mar 2004||11 Jul 2006||Ultradent Products, Inc.||Ball lens for use with a dental curing light|
|US7106523||11 Ene 2002||12 Sep 2006||Ultradent Products, Inc.||Optical lens used to focus led light|
|US7144250||17 Dic 2003||5 Dic 2006||Ultradent Products, Inc.||Rechargeable dental curing light|
|US7192276||20 Ago 2003||20 Mar 2007||Ultradent Products, Inc.||Dental curing light adapted to emit light at a desired angle|
|US7195482||30 Dic 2003||27 Mar 2007||Ultradent Products, Inc.||Dental curing device having a heat sink for dissipating heat|
|US8568140||23 Mar 2007||29 Oct 2013||Jozef Kovac||Apparatus and method for curing materials with radiation|
|US9066777||1 Abr 2010||30 Jun 2015||Kerr Corporation||Curing light device|
|US9072572||21 Jun 2013||7 Jul 2015||Kerr Corporation||Dental light device|
|US20060188836 *||19 Abr 2006||24 Ago 2006||Kerr Corporation||Apparatus and method for curing materials with light radiation|
|US20140334132 *||21 Ago 2013||13 Nov 2014||River Point, Llc||Medical Headlamp Optics|
|EP0120549A1 *||27 Abr 1983||3 Oct 1984||John Anderson Oram||Lamp unit|
|WO1994010499A1 *||4 Nov 1993||11 May 1994||David W Cunningham||Lighting fixture|
|Clasificación de EE.UU.||359/359, 362/804, 359/581, 359/890|
|Clasificación internacional||F21S8/00, F21V7/08, F21V8/00, F21V9/04, F21V9/08|
|Clasificación cooperativa||F21W2131/202, G02B6/0005, F21V9/04, F21V7/08, F21V9/08, Y10S362/804|
|Clasificación europea||F21V7/08, F21V9/08, F21V9/04, G02B6/00L4|