DE2219926A1 - Examination lamp - Google Patents

Description

PATENT LAWYERS DR.CLAUS REINLÄNDER S 6 P128 D DIPL-ING. KLAUS BERNHARDT

D- 8 MONKS 60 THEODOR-STORM-STRASSE 11 »

QTE SYLVANIA INCORPORATED, Wilmington, Delaware »USA

Examination lamp

Priority; May 10, 1971 - USA - Serial No. 141 742

summary

An examination lamp for medical, dental or the like purposes for use with an examination luminous dye such as sodium fluorescein is described which emits radiation, is limited essentially to the wavelength range between 380 and 505 nm and is free of infrared, yellow and ultraviolet. The lamp has a light source, for example an incandescent lamp, a dichroic reflector behind this lamp, with which blue light is reflected to the front and the rest is transmitted to the rear, a dichroic filter in front of the lamp, which charges blue light and reflects infrared to the rear , and an observation mirror for the irradiated parts, which reflects yellow light to the observer and transmits the remaining rays. The ultraviolet would indeed stimulate the fluorescein , but is filtered out because it is also natural

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ORIGINAL INSPECTED

Teeth, and some artificial teeth, stimulate fluorescence so that it would mask the fluorescence of the fluorescein

Background of

The invention relates to electrical lighting devices and in particular devices for medical and dental purposes »for example for examining the teeth of a Patients regarding stains (plaque) »tartar and the like, and for examination of the skin and eyes. Such devices should be called "investigation lamps" here.

Ultraviolet light from incandescent lamps with appropriate filters or from so-called black light lamps was previously used in devices of this type used «The former have a very poor efficiency and give very little light to the patient» and the latter are expensive and provide a source of information possibly dangerous rays because of the stronger ultraviolet light.

When using the device, the teeth or other body parts to be observed are first coated with a fluorescent substance treated, usually a small drop is enough to use on teeth and the resulting fluorescence is observed.

Bs has already been suggested on to be investigated To use a fluorescent dye on teeth or other parts, which can be excited to fluorescence by visible light, together with a filter with which the visible light can be absorbed both sides of the absorption curve is absorbed, the excitation? curve, which is important in this case, is in this proposal

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however not mentioned.

It was found that the use of ultraviolet Such an examination of the lamp with a fluorescent dye such as fluorescein is not effective, because the teeth fluoresce white themselves and therefore does not give a good contrast to the yellow fluorescence of the sodium fluorescence. It was also found that by cutting off part of the Excitation and absorption bands »in that the excitation radiation is kept above 330 nm, doh» above of the ultraviolet, and the excitation radiation is kept below 525 nm worldwide, i.e. that it is im has essentially been confined to violet and blue, with the tip in the latter showing a very strong yellow fluorescence can be obtained from fluorescein, which, against the nearly:. black background contrasted by that of the. Teeth themselves is formed "

This is unexpected because the wavelengths used to excite sodium fluorescein have hitherto been dubious. "The Merck Index - an Encyclopedia of Chemicals and Drugs" (8th Edition 1968; Merck & Co., Rahway, KJ ₀ , USA) states that sodium flioreszein responds best to radiation of 3600 AU (360 nm), ie one Radiation in the ultraviolet range. In "Pharmacological Basis of Therapeutics" (4th Edition) by Goodman and Gilman, states that the maximum absorption in water is 4935 AU (493 »5 nm), but that only adds to the confusion, and in any case it is The absorption maximum must necessarily be the excitation maximum. Even a non-fluorescent material has an absorption maximum, although there is neither an excitation maximum nor any excitation at all. ₀

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It was found that to achieve the maximum Excitation and the maximum effect of the yellow fluorescence the light from the search lamp at about 525 nm very much must be cut off sharply in order to emit as much visible excitation light as possible without being noticeable Light the color of fluorescein fluorescence is emitted. This can be done with a dichroic or interference filter can be achieved in front of an electric lamp, for example an incandescent lamp. The filter allows between 380 nm and 525 nm through and otherwise cuts off.

In order to increase the desired spectral range even further, a dichroic reflector can be used behind the lamp, to reflect light from 380 to 525 nm forward and to let the infrared pass backwards and out of the beam. If desired, the reflector can be all of the visible Reflect light and let the filter cut off the unwanted wavelengths

When the device is used, ambient light scatter can mask the fluorescence by illuminating the teeth directly However, it has been found that the use of a dichroic mirror to observe the irradiated teeth is very effective if it is designed to reflect light in the yellow, i.e. in the emission region, blue light and infrared, however, so that the observer is not disturbed by it. To prevent ambient light from getting through To get the mirror to the observer, a screen is preferably on the back of the mirror and at a distance from it appropriate. The distance gives an area in which the radiation transmitted by the front of the mirror is trapped is. The screen and any walls that surround the space

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"Limit mirrors around" should have low reflectance. The yellow light to be reflected is approximately between 560 and 590 nra. A patient can have light on his own teeth and look at the results in the mirror

The nature of diciritic structural elements leaves that Filter in front of the lamp also some long-wave red between 700 and 800 nm, this will make the device work but not bothered, because the eye for such long-wave red light is not very sensitive. However, the filter does not allow infrared radiation through but reflects it, so that the part of the body on which the radiation falls is not overheated. This warming by the infrared could otherwise be annoying

In this way it becomes a very compact search lamp for medical and dental use, although filters and one or more suitable lamps, if desired can be arranged in a large lamp on the ceiling, or in a different way.

However, the device is particularly useful in the form of a small lamp unit for observing a small area.

The lamp, the filter and the reflector can be held in position in a plastic housing, and in a portable unit the reflector could preferably, for most purposes, shine the light at a distance of about 5 to 10 approx. In front of the filter Unite focal point.

The diaphragmatic layers can be produced in the usual manner become, i.e. they can be set up in the floor, the one

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glass support plate roughly with a number of alternating Layers of magnesium fluoride and zinc sulfide coated with each layer about 1/4 wavelength thick.

The spectral transmittance of this coating for normal incident light should be as follows for best efficiency look

1. The mean permeability should be between 380 and 490 mn greater than 80 % , measured in steps of 10 nm, and no single valley ⁿ should be smaller than 70> 3.

2 _O The point 50 % transmittance in the blue-green should be between 495 and 505 nm

3ο The point 10 % transmittance in the blue-green should be between 510 and 525 nm.

The permeability between 550 and 660 na should be less than 2 %.

A certain deviation from these requirements is permissible, The larger the deviation, the worse it gets Effect.

A switch to switch the lamp on or off can be in the device can be built in so that the user has everything under his direct control «,

The invention will be explained in more detail with reference to the drawing;

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- 7 it shows

1 shows a longitudinal section through a device according to the invention Lamp; - '.... :

Fig. 2. the spectral energy distribution of the lamp, emitted light;

Fig. 3 is a front view of the device; and . . ·. :. Fig. 4 is a side view of the device »

According to FIG. 1, a tubular incandescent lamp 1 with its base 2 held in a conventional setting 3 »in which the threaded part 4 of the base fits, and which is attached to the housing 5 »In. Usually, the socket 3 provides an electrical contact to the outer metal part 6 of the base, and with the point. contact of the base 2, the point contact in the usual ¥ ice is attached to the metal part via an insulating glass stopper 9,

The lead wires 10, 11 lead through a sleeve 12 the housing 5, which in the usual way with a nut 13 is set on a thread 14 an.der sleeve 12. Of the. Wire 10 is electrical with the threaded portion of socket 3 connected and the wire 11 via a circuit breaker 15 and. . . Wire 16 with the socket «The wires are insulated.,. ,

The push button 17 actuates the switch 15 in the usual way, and is inserted into the housing 5 ₀ ... ...

The filament of the lamp 1 is located in or near the focal point of a reflector 18 _f shown in FIG

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Embodiment is an ellipsoid of which one focal point coincides substantially with the lamp filament and the other focal point is a few centimeters, about 5 to 10 cm, in front of the device. The reflector 10, for example the surface of a body of revolution, consists of glass and has a dichroic coating on the reflection surface. The dichroic coating is designed to reflect visible light and transmit infrared.

In front of the reflector there is a dichroic filter 20 which is flat; this filter reflects yellow Light and infrared back into the housing and lets blue through, so roughly speaking the opposite of what the reflector is does. The edge 21 of the reflector 18 is separated from the filter 20 by a helical spring 21; this spring lies against a Socket 22 of the filter 20, so that the reflector 18 is pushed back by the spring 21 so that it against a stop 22 of the housing 5 is applied.

Towards a dichroic mirror 23 is on a protruding, him surrounding holding arm 24 set on the front of the housing 5. The mirror is dichroic, it reflects yellow and lets through blue and infrared, and is under a corner set to a plane which runs transversely to the longitudinal axis of the optical system that consists of the reflector 18, the Lamp 1 and filter 20, and its position is 1st chosen so that rays from the teeth or the like. To the eye of the observer is reflected. An angle of about 10 ° has been found to be very effective for the illustrated embodiment proven, but the angle can be between 5 ° and 16 ° with good results.

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The external details of the housing are shown in FIGS. The words ^ top " _9, " front ".and the like relate to the illustration in FIG the light comes out of the device ... ■

In Fig. 2 is the spectral energy distribution of the device shown. It can be seen that the emitted light in the blue has a maximum at around 490 mn, and the emitted light lies between about 380 nm and about 525 nm, i.e. it extends from purple to green. There is no noticeable light in yellow and orange, only there is a in long-wave red second maximum, which is unimportant because the eye is very insensitive in this area. Fig. 2 shows the energy distribution the radiation from the device, and not the effect on the eye. .

The front view (Fig. 3) shows the observation mirror on the support arm 24, the front plate 25 »the front of the Housing 5 and the push button 17ο The profile (Fig. 4) shows the housing 5, the sleeve 12 and the push button 17o. The exterior of the device can also be designed differently.

The dichroic layers used in the described embodiment were placed on glass plates which were between 0.12 and 0.16 mm (0.047 and 0.062 ") thick. Lamp 1 was a 13 watt Device lamp with a T-7 bulb, i.e. a tubular bulb with a 7/8 "(22.2 mm) diameter,

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It is a vacuum lamp in which the Vfolframdraht operates at a comparatively lower temperature, lower than in the ordinary gas-filled flask, so that the The ultraviolet emitted by the filament is small, and the glass of the bulb further reduces it. The filter 20 has a fairly sharp drop between 350 and 380 nm, so that it also reduces some of the residual ultraviolet, this reduction in ultraviolet by the However, filtering is less necessary than would be necessary with a higher ultraviolet content source.

The filter 20 used in the illustrated embodiment had about 80 ° transmittance at 380 nm and about 370 nm 50 yes and at 350 nm G> j. At the other end of the let through In the range, the transmission at 490 nm was a little over 80 SS, boi 500 na about 60 #, at 505 nm about 40 yes and at 525 nm 6 55.

The filter 20 used was a dichroic or interference filter, with alternating layers of magnesium fluoride and zinc sulfide a quarter wavelength thick. The layers were deposited on a translucent glass support plate, the layer on the glass consists of fluoride, for good adhesion, and the top or 13th layer also made of fluoride, which has a harder surface than the sulfide. The mirror 23 in which the teeth were viewed was the same built up.

The reflector 16 has 20 layers, each about 1/4 wavelength thick, the layer on the glass being made of magnesium fluoride. The shifts then alternate and end in one Zinc sulfide layer on the outer surface.

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The layers can be applied in the usual way for dichroic components

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Claims (1)

S6 P128 D Claims ( 1 x examination lamp, characterized in that a reflector is arranged behind an incandescent lamp, with which blue light is reflected towards the front of the lamp and infrared light is transmitted, and a filter is arranged in front of the lamp, which transmits blue light and yellow light and Reflects infrared radiation. 2 · Lamp according to claim 1, characterized in that »the filter reflects ultraviolet radiation. 3 · Lamp according to claim 1 or 2, in which the lamp, the reflector and the filter are fastened in a housing, characterized in that an observation mirror is fastened on the outside of the housing in such a way that an observer using the light on his teeth, can see the result in this mirror. 4 «lamp according to claim 1,2 or 3» characterized labeled in ⁷ -eichnett that wavelengths below 380 nm are substantially eliminated from the emitted light " 5. Lamp according to claim 3 or 4, characterized in that the observation mirror is dichroic and has the same transmission and reflection properties as the filter. 6. Lamp according to one of claims 1 to 5 » characterized in that the filter has an average permeability greater than CO % between 380 and 490 nm, measured in steps of Λ0 nm, and not less than 70 % for any wavelength in this range, and that the point for 50 # permeability 209848/0671 ... / A2 - Ae-- table is 490 and 505 nm, the point 10 Sa transmittance in the blue-green is between 510 and 525 nm ₉ and the transmittance between 550 and 660 nm is less than 2 209848/0671