Multi-function light source

A multi-function dental operating light source comprises a plurality of optical filters and reflectors mounted upon a turntable at spaced locations around the periphery thereof, the turntable being rotatable to different predetermined positions relative to a collimated light source to produce selectable different modes of light delivery. The optical filters are adapted respectively to produce light beams for shade-matching, no-cure to prevent polymerization of light-curable resins when exposed to said light for observation purposes, a photocuring light beam, and beams for oral illumination and transillumination. The photocuring light is preferably developed by condensing the collimated light through a light-condensing cone or through an optical condensing system, the condensed light being delivered either directly from the condenser output or through a light pipe arrangement.

BACKGROUND OF THE INVENTION 
In modern dental practice, different types of illumination and photocuring 
functions are required and, at present, these, in general, are supplied 
respectively by individual different lamps packaged as separate light 
sources, thus requiring a number of individual pieces of equipment for use 
in a dental operatory. Also, at present, high rents necessitate 
maintaining operatory rooms in relatively small economical sizes, whereby 
the smaller, simpler, and less space-consuming equipment is, the better it 
can be accommodated comfortably in present day operatories. The present 
invention is directed to such minimizing of required illumination 
equipment as well as rendering the same more efficient and of improved 
quality. 
For many years, it has been customary for dentists to select operatories 
facing north wherever possible in order to obtain natural daylight as 
close as possible to pure white light, i.e., the absence of color hue. 
Such efforts are frustrated on cloudy or rainy days and the time of the 
year, however, whereby one has to resort to using artificial light from 
lamp sources upon which attempts have been made to modify the same to at 
least approach pure white light at an acceptable color temperature. 
Dentistry presently requires illumination of as nearly as possible pure 
white light to be directed at dental targets for viewing the same such as 
the interior of an oral cavity; similar somewhat intensified white light 
illumination suitable for shade matching of artificial teeth with natural 
teeth; photocure light power of a type to effect curing of light-curable 
resins or plastics used for dental restorations of various kinds and 
similar purposes; and illumination of dental targets of a type which 
permits viewing the same without effecting premature polymerization of 
visible light-curable resins or plastics, such as those used for dental 
restorations of various kinds and especially while forming and shaping 
fillings and similar restorations of plastic material prior to curing the 
same. As indicated above, lights or lamps to produce standard illumination 
now are available only as individual units. As far as is known, a no-cure 
type of illumination is not available to date. 
In the prior art of lighting and illumination in general, attempts have 
been made to utilize a single light source to produce, for example, 
different colors for entertainment and stage use. Typical examples of this 
type of illumination are illustrated in prior U.S. Pat. Nos. 2,606,477 to 
Leslie et al, dated Aug. 12, 1952 and 3,179,791 to Mole, dated Apr. 20, 
1965. As a slight modification of the principles illustrated in the 
foregoing patents, prior U.S. Pat. No. 2,699,536 to Roth et al, dated Jan. 
11, 1955 discloses a headlamp arrangement on certain vehicles for 
signaling purposes and in which the light source remains fixed and movable 
lenses cause the projections of a spiral pattern of beams. 
There also has been prior activity in reflecting beams from a light source 
in a manner to intensify beams therefrom by reflection to and from curved 
reflectors for ultimate direction through an output window or lens, one 
example being the subject matter of prior U.S. Pat. No. 3,202,811 to Hall, 
Jr., dated Aug. 24, 1965. 
Unlike the operation and construction of these cited prior art patents, the 
present invention utilizes a single lamp as a light source and by means of 
a series of light modifying optical filters and related elements, coupled 
with variable control of voltage to the filament of the light source, at 
least most if not all of the various types of dental applications for 
illumination and photocuring set forth above can be produced by relatively 
simple structures of a compact nature, details of which are set forth 
below. 
The present invention is the result of expanding and increasing the 
versatility and convenience of the inventions in Applicant's prior U.S. 
Pat. No. 4,385,344, dated May 24, 1983, U.S. application Ser. No. 492,286, 
filed May 6, 1983 still pending, and parent application Ser. No. 566,235 
now U.S. Pat. No. 4,516,195, filed Dec. 28, 1983. 
SUMMARY OF THE INVENTION 
Among basic objects of the present invention, it is a major objective to 
provide a multi-function light source, for dental and other uses, which 
employs a single light source and a rotatable turntable having mounted 
thereon a limited number of light beam modifiers of said light source, for 
selective positioning relative to said light source, whereby a plurality 
of required dental illumination needs and photocuring functions are 
supplied by a single instrument. 
Ancillary to the foregoing object, it is a further object to have said 
single instrument selectively supply substantially pure white light to 
view dental targets, intensify said white light at a higher color 
temperature a limited amount for shade matching purposes simply by varying 
the voltage to the lamp filament by adjusting a potentiometer, supply 
non-polymerizing light illumination for viewing dental materials which 
otherwise would light polymerize light-sensitive materials, and supplying 
polymerizing light capable of quickly polymerizing light-polymerizable 
resins and plastics when required, whereby simple rotation of the 
aforementioned turntable on which said several light-modifying optical 
devices are supported in spaced relationship produces the desired types of 
dental illumination and photocure function from a single light source. 
Another object of the invention is to provide a heat-absorbing filter 
positioned adjacent and in the path of the light beam emanating from a 
collimated light source, whereby the light beam is intercepted by the heat 
absorbing filter and produces relatively cool light, of reduced infrared 
wavelengths, and less thermal stress is placed upon the modifying optical 
filters when positioned in the light beam and in front of the reflector of 
the lamp. 
A further object of the invention is to provide as a light source a 
tungsten halogen lamp having a parabolic reflector to produce 
substantially parallel light rays, and further to provide one or more 
light filters selectively positionable in the light path from the lamp and 
the reflector therefor. Beam-splitting flat mirrors also are positioned in 
the standard illumination beam and the no-cure beam which split the light 
beam into two separate light beams transmitted through said optical 
filters and reflect the same in separate directions respectively to 
spherical reflectors positioned at opposite sides of said lamp. Since each 
of the split beams are spaced apart, they reflect each of the beams 
forward, toward and through a fixed transparent window spaced forward from 
said lamp. Each of the separate light beams reflected from said spherical 
reflectors cross each other at a specified distance from said reflectors 
and are blended with the other beams to provide an illumination area of 
limited width and height at a location spaced forward from said window. 
The crossover of said light beams is at a range of distances at which a 
dentist normally positions an illuminating light source from a dental 
target such as an oral cavity. One reason for dual converging light beams 
is that, when a dentist is manipulating, it is possible to block one light 
beam with an arm, shoulder, hand, or head, whereby one light beam is left 
unblocked for illumination purposes. 
Still another object of the invention is to provide a base movably mounted 
relative to a dental chair in an operatory for desired positioning of said 
base relative to a patient in said chair, and said aforementioned 
turntable upon which said aforementioned beam-modifying optical filters 
are mounted and is rotatably supported upon said base for movement around 
an axis vertical to said base, and further providing releasable 
position-maintaining means between said turntable and base to firmly hold 
a selected beam-modifying optical filter and associated beam-splitting 
flat reflectors in operable position adjacent said aforementioned lamp. 
A further object ancillary to the immediate foregoing object is to mount 
said lamp fixedly and centrally adjacent one side edge of the base, which 
preferably is a plate, and also fixedly position said aforementioned 
spherical reflectors adjacent said same side edge of said base plate and 
spaced from opposite sides of said lamp, and said aforementioned 
transparent window is fixed to the opposite side edge of said base plate. 
Still another object of the invention is to utilize optical filters and 
related mechanisms to change illumination emanating from a light source 
such as, for example, a tungsten halogen lamp, which filter system 
produces various desired Kelvin ranges respectively arranged to produce: 
(1) white illumination with a color temperature between 4700.degree. K. 
and 5100.degree. K. for normal observation of dental targets; (2) for 
color matching purposes, intensify the blue, green, and red toward the 
blue and thereby increase the lumens for shade matching by raising the 
color temperature to about 5500.degree. K. or in a range between 
5400.degree. K. and 5900.degree. K.; (3) for placing light cured dental 
restorations, without initiating curing, reduce the color temperature to 
less than 1667.degree. K. and use the same with a filter which eliminates 
the blue range of the spectrum between 400 and 500 nm, and permits 
wavelength greater than 500 nm to pass through the optical filter, which 
renders polymerizing of visible light-polymerizable resins and plastics 
unaffected by the light; and a light beam having sufficient energy to 
polymerize actinic light activated materials. 
.degree.K. arranged to be delivered to a light condensing means to 
polymerize actinic light activated materials. 
It is another object of the invention to provide a multi-function, or 
multi-mode light apparatus for delivering light in selectable different 
modes derived from a collimated light source, at least one of the modes 
including a beam or beams of light and another mode including light 
delivered through a light pipe, with condensing means for condensing light 
from the source into the light pipe. 
Details of the foregoing objects and of the invention as well as other 
objects thereof, are set forth in the following specfication and 
illustrated in the accompanying drawings comprising a part thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION 
It is believed desirable to set forth herein certain definitions and 
criteria pertinent to the present invention as follows: 
Photometric power is that which the eye sees expressed in lumens/square 
meter or lumens/square foot. 
Radiometric power is actual power from a given source expressed in 
watts/cm.sup.2. 
Nanometer (nm) is a unit of length of one cycle equal to one billionth of a 
meter or 10.sup.-9 meters. 
Lumen (Lm) is a unit of luminous flux. 
Footcandle (fc) is a unit of illuminance equal to one lumen per square 
foot. 
Lux (Lx) is a unit of illuminance equal to one lumen per square meter. 
Kelvin (K) is a unit of temperature equal in magnitude to 1.degree. C. but 
based on an absolute temperature scale in which 0.degree. 
K.=-273.15.degree. C. 
Wavelength is the distance between two successive points of a periodic wave 
in the direction of propogation of a beam of light. 
Hue is the attribute of a light source or object that determines whether it 
is perceived as red, orange, yellow, green, blue, or violet, without 
regard to the other aspects such as saturation and brightness. 
In accordance with the present invention, the light source preferably is 
generated by electric current connected to a tungsten halogen lamp having 
a parabolic reflector, but other lamp types may be used such as various 
arc-type lamps which produce an acceptable optical spectrum. One 
particular selected tungsten halogen lamp found to be highly successful 
can be operated as high as 3400.degree. K., but this is only exemplary and 
not restrictive. With this as a benchmark, however, for purposes of 
illustrating at least one example of the invention, the various lights or 
illuminations designed to be produced by such lamp require the use of 
specific optical filters to achieve the objectives of the invention for 
different dental illuminations and for photocuring purposes. In order to 
effect relatively cool light beam operation of the multi-function 
illuminating system of the invention, a heat absorbing filter preferably 
is positioned immediately in front of the lamp relfector in the light 
beam. With this exception, all of the other optical filters are 
interference filters which either pass or reject certain wavelengths of 
light, as designed and desired. These optical filters comprise layers of 
certain materials selected for their known index of refraction and are 
laminated, for example, in a vacuum deposition chamber, and laid on a 
suitable substrate. Such optical filters shape the spectrum of a light 
beam pssing therethrough to a desired portion or section of the optical 
spectrum for specific passage or rejection of light beams of various 
wavelengths. 
Light beams also have color temperature units expressed as K or Kelvins. 
According to one specific set of examples of ranges of color temperatures, 
but without limitation thereto, relative to the present invention, the 
optical filter to produce substantially pure white light for normal 
illumination of dental targets from the reflector of the lamp referred to 
produces beams having a color temperature between 4700.degree. K. and 
5100.degree. K. in the wavelength range between 400 and 715 nm and in 
which the blue, green, and red wavelength ranges are proportioned to 
produce pure white light. 
For shade matching of artificial teeth with natural teeth, this temperature 
is increased to approximately 5500.degree. K. but with an adjustable range 
from 5400.degree. K. to 5900.degree. K. which is accomplished by 
increasing the voltage beyond the standard illumination range supplied to 
the filament of the lamp. 
For observation of a dental target which requires illumination and, 
therefore, exposure of light-curable resins or plastics to certain beams 
without activating the material, a filter to produce a beam having a color 
temperture of less than 1667.degree. K. is used but the filter is one 
which eliminates the 400 to 500 nm wavelength range, yet retains light 
beams between the 500 and 715 nm wavelength range which is necessary for 
viewing purposes and allows placing and shaping the observed 
light-sensitive material such as visible light-curable filling or denture 
base resins or plastics. Such beams are in the yellow-red region of the 
spectrum. 
For curing light-sensitive resins and plastics, the invention includes a 
photocure heat reflecting band pass filter positionable opposite the 
parabolic reflector of the lamp, which heat absorbing filter which has a 
color temperature of less than 1667.degree. K. with its light flux 
primarily in the 400 to 500 nm wavelength range and which rejects beams in 
the wavelength range betwewen 500 and 715 nm. A light-condensing means, 
either optical or in the form of a cone, is used when photocuring is 
required. 
In producing the above-described types of illumination and for photocuring 
purposes, another objective of the invention preferably is to project 
beams from the apparatus in a collimated form and of reasonable dimensions 
in an area at a conventional distance of approximately in the range of 
between 24 and 37 inches between the dental target and the light source. 
In an alternate embodiment, the light is condensed and directed into a 
flexible light tube, for delivery of a high intensity light to a 
relatively small target area. 
As an improvement ancillary to the foregoing object, the circuit to the 
lamp also includes an additional, preferably push-button, switch which is 
actuated easily to restore current to the lamp after the external 
supplmental cone has been mounted operatively upon the internal primary 
cone and, still further, a timer of limited time duration also is in the 
lamp circuit and functions to disconnect current from the lamp after a 
pre-set time elapses, such as ten seconds duration, for example, thereby 
automatically limiting exposure by the photocure light beam. The above 
described push-button switch may be actuated repeatedly, however, to 
afford as much photocuring as required. 
Having set forth above exemplary parameters of physical aspects of the 
illuminating apparatus of the present invention, it is to be understood 
that the criteria described may be changed within reasonable limits 
without departing from the spirit of the invention. Specific illustrations 
of physical apparatus which utilize said criteria are set forth below. 
The Apparatus 
Referring to FIGS. 1 and 3 of the drawings, it is intended that the 
multi-function dental operating light source comprising the present 
invention by supported by the outer end of an appropriate arm 10 which 
extends either from a wall, ceiling, or post pedestal in an operatory. A 
U-shape member 12 is connected by a swivel 14 to the outer end of arm 10 
and it will be understood that an electrical supply cord is located in 
conduit 16 and extends from a suitable power line source, not shown, and 
appropriate electrical thermal breakers, current-limiting switch, and 
connect-disconnect switch and its wiring are located in said conduit which 
extends in conventional manner through the arm 10, swivel 14, and U-shape 
member 12 to the interior of the light head housing 18 which preferably 
comprises an upper section 20 and a lower section 22 that are detachably 
connected. Opposite sides of the housing 18 are connected by pivots 24 to 
the outer ends of member 12. 
The sections 20 and 22 of housing 18 preferably are molded from suitable, 
rigid plastic material for durability as well as to provide electrical 
insulation properties. Further, a manually-engageable handle 26 extends 
from each of the opposite sides of the housing 18 for purposes of 
swivelling the housing to any desired location and position for purposes 
of directing illumination or photocuring light beams therefrom to a dental 
target such as an oral cavity or tooth of a patient. It will be understood 
that the pivots 24 and swivel 14 have sufficient friction to maintain a 
desirable location and position of the housing 18 after the same has been 
adjusted to a working position. 
Referring particularly to FIG. 3, a description of the contents of the 
housing 18 is as follows. In said figure, it will be seen that there is a 
base 28 which preferably is a plate substantially parallel to the meeting 
lines of sections 20 and 22 of the housing, said base plate preferably 
being of metal, such as aluminum, and may be anodized black or in color. 
Elements 32 comprise the upper portions of posts which extend 
perpendicularly from base 28 and extend through suitable holes in the base 
plate. The lower part of the upper portions 32 are threaded to receive 
clamping nuts 34 and accomplish this without threading the entire portions 
32 by the part thereof which receives the nuts 34 being of a slightly 
larger diameter than the upper part of said portions. The outer ends of 
upper portions 32 have tapped holes, not shown, for purposes of receiving 
connecting screws 38 which extend through bases 40 shown in FIG. 1 on the 
interior of the upper and lower sections 20 and 22 of the housing 18. FIG. 
3 reveals the upper portions 32 of four composite posts (not shown) 
respectively adjacent the corners of base 28. These composite posts 
comprise the means for holding together the upper and lower sections 20 
and 22 of the housing 18. 
The front wall of the housing 18 has a transparent window panel 42 which, 
in vertical elevation, is shown in FIG. 2 in the forward portion of the 
housing 18 and has a bezel 44 surrounding the same. Said bezel has a 
continuous groove 46 extending thereinto as best seen in FIGS. 2 and 3 and 
said groove receives the edge portions of the transparent window panel 42 
for purposes of securing it in operative position. The panel has a small 
opening or apertue 48 near the upper portion and midway between the 
opposite sides through which the photocuring light can pass when the same 
is open, details of which are described hereinafter. The opening 48, 
however, normally is closed except when the external light-condensing cone 
is mounted upon the primary internal cone, whereby its effects are 
employed to activate light-curable resins and the like when aligned with 
said opening. Closing of opening 48 is effected by a closure in the form 
of a pivoted plate 50 which is shown in edge view of FIG. 3 in the lower 
portion of said figure. The closure 50 is supported upon a pivot bolt 52. 
To manipulate the closure, a pin 54 which is attached thereto projects 
through the opening 48 as clearly shown in FIG. 2. It is otherwise shown 
in FIG. 3, where it will be seen that it is adequate for manual 
engagement. Closure 50 normally is maintained in closed position in a 
yieldable manner by means of return spring 56. The window panel 42, in 
each of the opposite upper corners thereof, is provided with clear 
transparent window portions 58 and, otherwise, the window panel 42 is 
opaqued, such as by painting the inner surface thereof or otherwise. The 
lower opposite corners of the window panel 42 also are provided 
respectively with holes through which a push-button actuator 60 and a 
shaft of a potentiometer extend. 
Base plate 28 supports a number of elements within housing 18, among the 
more important of which is a turntable 64 which is shown in plan view in 
FIG. 3. Said base is provided with a preferably circular opening 66 into 
which a shouldered, preferably circular insulating insert member 68 is 
suitably affixed by spaced screws 70, certain of which are shown in FIG. 
3. Rotatable shaft 72 extends through a central opening in insulating 
member 68. 
Shaft 72 has a depending portion which extends through the lower section 22 
of housing 18 as shown in FIG. 1 and to the projecting end thereof, a 
manually-engageable, rotatable knob 98 is affixed. The foregoing 
arrangement is for purposes of positioning the plurality of different 
beam-developing devices circumferentially mounted upon the turntable 64 
relative to a light source, details of which are described hereinafter. 
Base 28 is fixedly mounted within the housing 18 by means of the details 
not shown. Also supported fixedly upon said base plate is a lamp housing 
100 provided with an insulating base insert 102 which receives and 
supports base plate 104 of a preferably tungsten halogen lamp 106 which 
has a parabolic reflector for purposes of producing a collimated light 
beam. The housing 100 has a pair of ears 108 which are secured by screws 
to the base 28 as clearly shown in FIG. 3. Connected to insulating base 
insert 102 are a pair of electric wires 110 which are part of the electric 
cord 16. 
The forward portion of the lamp housing 100 has an opening through which 
the collimated light beams from the parabolic reflector of lamp 106 are 
projected and extending across that opening is a heat absorbing filter 
112. Further for purposes of rendering operation of the multi-function 
light source within a dental operatory relatively cool, supported adjacent 
an opening in the fixed base plate 28 and upon the lower surface thereof 
is a forced air cooling fan unit 114, shown in phantom in FIGS. 1 and 2 
and in plan view in FIG. 3, said unit including a bladed fan 160 which 
blows ambient room air directly through the housing 100 and in doing so 
draws air in through louvre 118 in the lower section 22 of the housing and 
discharges it through louvre 118 in the upper section 20 of the housing 
18. 
The Turntable 
As described hereinabove in a general manner in the objects of the 
invention, one of the highly important features of the present invention 
comprises the turntable 64, the mounting of which is described 
hereinabove, and of the light beam-modifying elements which are supported 
thereon for rotation therewith to dispose the same respectively in one of 
three operative positions relative to the fixed light source 106 which 
preferably is a tungsten halogen lamp but other lamps of suitable and 
similar capability to produce a suitable optical spectrum may be 
substituted therefore, if desired. By actual experience, however, it has 
been found that said specific type of lamp performs admirably for all of 
the purposes to which the present invention is directed. Also as indicated 
above, there are three principal types of light beams capable of being 
produced by the invention by means of certain individual filters 
respectively producing (1) pure white illumination meaning the absence of 
color hue, (2) no-cure illumination, and (3) photocuring power. 
With reference to FIG. 3, it will be seen that the base 28 supports a 
spring-actuated positioning unit 120 which releasably engages 
complimentary shallow recesses 122 in the periphery of the turntable 64 to 
accurately position the various beam-modifying optical elements. The first 
beam-modifying optical element or system comprises a perpendicular frame 
124 which supports a perpendicular filter 126 adapted to develop from lamp 
106 and adjacent reflectors a standard illuminating beam which is pure 
white and devoid of color hue. Opposite the frame 124 is a similar 
perpendicular frame 128 which supports a no-cure filter 129. The light 
beams from filters 126 and 129, when they individually are disposed 
adjacent the lamp 106 and in axial alignment thereof respectively are 
divided by angularly positioned reflecting flat mirrors or light 
beam-dividers 130 and 132 which are secured by means of a bracket through 
which screws 134 project for securing the brackets to the turntable 64. 
One set of such reflecting mirrors 130 and 132 are provided respectively 
for each of the filters 126 and 129. 
Mounted between the sets of reflecting mirrors or members 130 and 132 is a 
diametrically extending light reflecting device comprising a 
frustro-conical light-condensing cone member 136. The light output end 138 
of member 136 is smaller than the operative light input end which is shown 
in FIG. 3 to be adjacent the lamp 106 for purposes of receiving collimated 
light rays from the parabolic reflector of lamp 106. The light rays also 
pass through a heat reflecting and band pass filter 140 for purposes of 
reshaping the optical spectrum of the light-curing beam. 
Standard Illumination Beam 
Referring to FIG. 4, it will be seen that the filter 126 is disposed 
adjacent the heat absorbing filter 112 and in immediate alignment with the 
parabolic reflector of tungsten halogen lamp 106. Adjacent the rear edge 
of the base, somewhat at the corners thereof, are a pair of spherical 
reflectors 144 and 146 which are shown better in FIG. 3. These have been 
adjusted to receive light from the divided beams from the flat mirrors 130 
and 132 which, in turn, reflect the light forward through the clear 
transparent window portions 58 of the front panel 42. Light rays reflected 
from the spherical reflectors 144 and 146 will travel nearly parallel to 
each other and spaced apart as shown in FIG. 4 while others will cross 
each other at defined distances as also shown in said figure, the result 
being that a column of light beams for standard illumination, comprising 
pure white light, are developed over a reasonable area 148 which, at a 
distance of about between 24 and 37 inches from a dental target will be in 
the range of approximately 4 inches high and 8 inches wide, such 
description primarily being exemplary rather than restrictive. 
The beams produced will be of a pure white nature, free of color hue due to 
the nature of a filter 126. Further by way of a specific example, assume 
that the color temperature of the lamp 106 is approximately 3000.degree. 
K. The filter 126 produces a color temperature within the range of 
4700.degree. K. and 5100.degree. K., the wave length range being between 
400 nm and 715 nm. The same type of white light also is preferable for 
shade matching of artificial teeth relative to natural teeth or any other 
objects requiring color comparison but preferably such light must be of a 
higher color temperature such as of the order of 5000.degree. K. This is 
produced also by optical filter 126 but the voltage to lamp 106 is 
increased by manipulating the knob 62 connected to potentiometer 150, as 
seen in FIG. 3. Knob 62 and potentiometer 150 suitably provide a plurality 
of positions for setting the voltage applied to lamp 106, and thus its 
corresponding lamp temperature. This combination is also used to provide 
discrete voltages to the lamp for the embodiments of FIGS. 7A, 7B, and 7C 
discussed below. 
No-Cure Illumination 
Referring to FIG. 5, this illustration pertains to the no-cure illumination 
light beam and to produce this, the turntable 64 is rotated to position 
optical filter 129 opposite the lamp 106, where it will be held by means 
of one of the depressions 122 in the turntable engaging the spring-pressed 
ball detent of the positioning unit 120. Optical filter 129 is different 
from optical filter 126 in that it is designed to reject beams having 
wavelengths between 400 and 500 nm and therefore are not present in the 
light beam produced of the lamp whereby the resulting non-curing light 
beams are in the blue region of the visible spectrum and are incapable of 
ploymerizing light-polymerizable plastic. However, the optical filter also 
is capable of passing the light beams between 500 and 715 nm for purposes 
of viewing light-curable material, without activating it, such as when the 
same is being placed, contoured, and characterized in a tooth or teeth. 
The passage of light beams between 500 and 715 nm is suitable for such 
illumination and viewing purposes and is in the yellow-red region of the 
visible spectrum. 
As is in regard to the description relative to FIG. 4, the light beams 
produced by the parabolic reflector of lamp 106 and filter 129 are 
reflected by the spherical reflectors 144 and 146 to project foward both 
the parallel light beams and those which cross at defined distances and 
ultimately result in producing an illuminating area 148 within the ranges 
stated with respect to optical filter 126 in FIG. 4. 
Photocuring Light Power 
When the photocuring function is to be produced by the invention, the 
turntable 64 is rotated to the position shown in FIGS. 3 and 6 in which 
the internal primary condensing cone member 136 is disposed with the 
larger light input end adjacent the lamp 106 and the outer smaller light 
output end 138 thereof immediately adjacent the opening 48 in the window 
panel 42. The light-condensing primary cone member 136 may have a 
supplemental externally mounted light-condensing cone member 152 (FIG. 6) 
attached to its output end 138 by friction or otherwise, to effectively 
extend its length. Support 154 is fixed at its lower end to turntable 64 
and, in addition to supporting the heat reflecting and band pass filter 
140, also supports the larger inner end of the primary light-condensing 
cone member 136, while the smaller end 138 thereof is supported by a 
bracket 156 and is attached by screws to turntable 164 as clearly shown in 
the lower portion of FIG. 3. 
Preferably, the interior of light-condensing cone member 136 has a highly 
specular light-reflective surface which, for convenience, for example, may 
comprise a highly polished electrobrightened aluminum interior liner, and 
similarly, such liner lines the inner wall of the supplemental external 
light-condensing cone member 152 which, when rendered operative, is 
extended through the small opening 48 in the window panel 42 and then is 
mounted upon the small end 138 of internal light-condensing cone member 
136. A substantial amount of collimation of light rays from the reflector 
of lamp 106 occurs when mounted as shown by phantom lines illustrated in 
FIG. 6 by the beams delivered from the discharge end of supplemental 
external light-condensing cone member 152 which diverge only to a limited 
extent of about 10.degree. from the optical axis in order to provide 
greater penetration of a light-curing beam into light-polymerizable or 
photocurable plastic material. A low light ray divergence angle is 
desirable for purposes of activating the same and thereby produce a rigid 
dental restoration having a greater depth of cure. In normal operation, 
the tip or outer end 158 is disposed relatively close to the dental target 
which is to be activated by the light energy emanating therefrom. 
When a turntable is disposed in the position shown in FIGS. 3 and 6, 
wherein the member 136 is in active position for receiving beams from the 
lamp 106 and assuming that the member 136 is directed toward a patient's 
face such, for example, as when it is positioned for purposes of having 
the supplemental member 152 affixed thereto, the intense light emanating 
from the internal primary light-condensing cone member 136 is very bright 
and would present a safety problem as well as being very annoying to a 
patient if directed thereto. To prevent this from occurring, the invention 
contemplates the use of a disconnecting switch 160, which has an actuating 
finger 162 engaged by a camming roller 164 which is shown adjacent the 
finger 162 in FIG. 3. It will be seen that when the turntable 64 is 
rotated, for example, from either of the positions shown in FIGS. 4 and 5, 
to the position shown in FIG. 6, the finger 162 will be engaged by the 
roller 164 and open the switch and thereby disconnect the lamp 106 from 
the supply circuit so that it will not shine through the open end 138 of 
member 136. 
After the supplemental external light-condensing cone member 152 has been 
attached over the outer end of member 136, as shown in FIG. 6, an 
additional switch 166, as seen in FIG. 3 in the lower left-hand corner, is 
actuated by push-button 60 to re-establish the current to the lamp 106 for 
the purpose of creating light beam 168 which is of a light-curing nature 
and emanates from the light output end 158 of the external 
light-condensing cone member 152. 
Referring now to FIGS. 7A, 7B, and 7C there are shown plan views of an 
alternate embodiment, wherein a different turntable arrangement is 
utilized for providing a different combination of selectable light modes, 
i.e., forms of light delivery. The turntable is rotatable in a manner as 
set forth above, to provide different combinations of light outputs in 
accordance with the elements that are brought into the path of the light 
source at the respective turntable positions. 
FIG. 7A shows the turntable in a position to generate three light beams for 
general illumination, plus a light pipe output for transillumination of 
small target areas. In this arrangement, the potentiometer 150 (FIG. 3) is 
set by the operator to provide a voltage setting of, e.g., 32, 35, or 38 
volts, corresponding to a bulb temperature of about 2864.degree. K., 
3009.degree. K., or 3075.degree. K. respectively. A pair of reflector 
mirrors 230, 232 mounted on a support 236 are positioned to reflect light 
from collimated source 206 toward and off of spherical reflectors 244, 
246, to provide two converging beams. In addition, support 236 contains a 
slot, or window 237 positioned just below reflectors 230, 232, as further 
illustrated in FIG. 8. This slot permits a portion of the light from 
source 206 to pass directly through above the center of the turntable. 
Much of the beam passes through to focusing lens 245, which is held in 
position by support 247 having a window 248. The lens and window are 
positioned to direct the center beam of light so that it substantially 
meets with the two converging side beams at a predetermined distance. Also 
shown in FIG. 7A is the input end 270 of a light pipe 278, having an input 
tip 271 positioned to collect slightly off axis light from the center 
beam. The lamp 106 produces substantially collimated light, but some light 
diverges off axis, and tip 271 is positioned slightly off the axis of the 
center beam. As seen in FIG. 8, the light pipe is connected mechanically 
to cover 274 through ring or collar 275, the main portion of light pipe 
278 being flexible and of a sufficient length to enable the dentist to 
direct the output end 280 at any desired target location. The input tip 
collects essentially off axis light from the center beam, while the bulk 
of the collimated portion of the beam passes on to and through window 248. 
The light pipe 278 thus provides additional ability to capture the off axis 
light of the center beam, e.g., an operator can additionally direct the 
light pipe output to transilluminate tissues in the oral cavity, such as a 
tooth, or the light pipe may be used for high intensity spot illumination, 
such as in the posterior areas of the oral cavity. 
Referring now to FIG. 7B, the turntable 264 is shown rotated into another 
position so as to provide only a photocure light for light curing 
procedures. For this application, the lamp is preferrably operated at 47 
volts, corresponding to a lamp temperature of about 3254.degree. K. The 
collimated light from source 206 is condensed and direced into the tip 
portion 270 of light pipe 278, providing intensified light for purposes of 
light curing of a restoration. A condensing means particularly adapted for 
this application comprises a spheric lens 250 and biconvex lens 256. This 
combination provides a very short focal length condensing means of the 
collimated light, e.g., 1 cm distance, and directs it into the tip 271 of 
the receiving portion 270 of the light pipe. A band pass filter passing 
visible light in a range of about 400-500 nm is mounted between spheric 
lens 250 and the biconvex lens 256. Further, a shield 252 prevents 
scattering of light from the spheric lens toward either reflector 244 or 
246, ensuring that no light is directed toward the patient from those 
reflectors. Any straight ahead light is blocked by the back side of mirror 
support 261. Thus, the high intensity cure light is available through the 
light pipe, while at the same time the patient is shielded from any other 
light beam being directed on his or her face. As illustrated in FIG. 8, 
the light pipe 278 is flexible, and can be manipulated by the operator to 
direct the output end 280 at any desired target, e.g., a photocurable 
restorative that has been placed in a patient's tooth. 
Referring now to FIG. 7C, there is shown a third position of turntable 264, 
providing for two converging beams reflected from reflectors 244, 246, the 
beams being filtered additionally by color correction filter 260 for shade 
matching purposes. Filter 260 is illustrated in a position directly in 
front of source 206, and is designed to modify the source light spectrum 
from the parabolic reflector such that the visible light power 
distribution in the beams delivered to the target meet the color rendering 
index greater than 90 required for shade matching of teeth, particularly 
for matching of new artificial teeth to natural or tooth surfaces, as 
described above in connection with the embodiment of FIG. 4. Mirrors 262, 
263 are also rotated into position, to reflect light off of reflectors 244 
and 246, thereby generating two converging beams for the shade match 
application. Since there is no window in support 261, there is no 
straight-ahead beam, and there is no light that gets through to the light 
pipe tip 270. For this application, the lamp is operated at a voltage of 
about 41 volts, corresponding to a lamp temperature of about 3175.degree. 
K.