EP0056505B1

EP0056505B1 - Electrically focused surgical light

Info

Publication number: EP0056505B1
Application number: EP81300165A
Authority: EP
Inventors: Kenneth J. Fisher; William R. Miller
Original assignee: American Sterilizer Co
Current assignee: American Sterilizer Co
Priority date: 1981-01-15
Filing date: 1981-01-15
Publication date: 1987-07-22
Also published as: EP0056505A1; ATE28503T1; DE3176330D1

Abstract

A multifilament lamp combination (12 min or 121) is disclosed which may be used alone and in multilamp arrangements with other single and multifilaments lamps (12 min or 121) to provide pattern size variation from a large diameter flood effect to a smaller diameter spot effect. A spot/flood capability exists to provide large pattern exposure simultaneously with secondary spotlighting. The filaments (15 and 16; or 123, 124, and 125) can be energized selectively from a remote switching station (D) so that the individuals who are scrubbed and gloved need not touch any part of the switching arrangement (D) to change the lamp pattern size. A cluster of lights (111 through 113) can contain one or more is multifilament lamps (121) within the cluster, so that by switching on the rear most filament (123) of the multifilament lamps (121) and switching off the single filament lamp, a small high intensity pattern is obtained by switching to the other filaments, a large pattern of high intensity is formed. More than two filaments can be provided in each lamp (12 min or 121).

Description

This invention relates to filament type electric lamps and particularly but not exclusively to surgical lamps or lights.
A known filament type electric lamp is summarised in the precharacterising portion of Claim 1 and is known from US-A-3 493 806.
In US-A-3 493 806 there is described an incandescent light for use in automobiles, including a tubular bulb having a main filament and a dipping filament, the main filament being positioned at the focal point of a single fixed parabolic reflector with corresponding light rays projected as a horizontal beam, the dipping filament being axially spaced from the main filament. Screen means are located on the exterior surface of the bulb so as to prevent those rays from the dipping element which would be reflected upwards, from striking the reflector.
It is also known from US-A-4 037 096 to have an illuminator for surgical lighting comprising a single light source contiguously located along the axis of symmetry of the illuminator, and multiple reflectors arranged such as to project light rays in a converging light pattern of uniform light intensity.
In the specialized lighting utilized for surgical procedures, it is frequently desirable to be able to adjust the pattern size of the light pattern on the wound site depending upon the particular procedure being used and/or the progress of the operation during the surgical procedure.
The light disclosed herein provides an improvement over the surgical lamp shown and United States Patent No. 4 037 096 and United States Patent No. 4 025 778. The latter patent shows a plurality of lights that are arranged mechanically to change the position of the focus of the lights. This requires complex apparatus and considerable physical effort.
Thus the conventional means of accomplishing a change in focus and/or a change in pattern size is by mechanical movement of the bulb relative to the reflector or reflectors of the optical system. This normally involves utilization of a lever or levers located on the light itself in order to initiate physical lamp source displacement. Since the lever or levers are not sterilized prior to the surgical procedure, it would be a break in technique if any of those individuals who are scrubbed and gloved should touch such levers to vary focus or pattern. Thus, such focus means are inconvenient. To provide for remote operation of focus would require a very cumbersome motor drive being mounted on the light.
It is an object of the present invention to provide a means for controlling the pattern size and/ or focus of such surgical lighting without the requirement for mechanical movement thereby facilitating remote operation and control.
It is a further object of the present invention to provide a means of electrically controlling the pattern size of a surgical light by the utilization of a multiple filament bulb with suitable means to activate one filament or the other. This provides a means for the pattern size to be changed by remote control without anyone having to physically touch the lamp itself.
The present invention is summarised in the characterising portion of Claim 1. By switching on the light sources at different distances from the reflector, the pattern of light from the lamp on to an object on a surgical table can be changed.
By energizing one or the other of the filaments, the focus and, therefore, the pattern size can be changed electrically. As a side benefit to this arrangement, in the event a filament should burn out during a surgical procedure, the light could be switched over to another filament and the surgical procedure continued without having to pause to relamp the light. (In particular, there are some countries that require such standby lighting capability in surgical lighting.)
The present invention envisages the use of a bulb with two or more filaments spaced a predetermined controlled distance apart relative to the axis of the optical system. Since two or more filaments can be placed within the lamp, a multiple of patterns can be achieved by expanding the number of lamps. The design allows for dual filament capability in small lamp envelope packing configurations. Previous designs were of the standard incandescent variety, which were bulky and suffered from shortcomings of lumen depreciation and reduced life. The lamps employed herein are the frosted, low voltage type using the multiple filament technology to overcome these negative attributes. Also, the associated small envelope approximates a point source and allows it use in multi-reflective systems offering a greater range in pattern/focus selection. The curvature of the reflector may be parabolic with the filaments located between the reflector and the focal point of the reflector, so that the rays of light come to focus at a finite point.
A cluster of lights could contain one or more multi-filament lamps within the cluster. Therefore, by switching to the rearmost filament on the multi-filament lamps and switching off some of the lamps, a small pattern of high intensity can be obtained. By switching to the other filament and switching on additional lamps, a large pattern of high intensity can be formed. This design compares with hitherto multicluster systems which decrease overlap of fixed light projections from the various lamps and hence pattern size by switching off lamps. Consequently intensity is decreased as the pattern becomes smaller.
A derivative of this system has applicability to the field of photographic lighting. It is well known that the two principal types of lighting used by photographers are "Flood" and "Spot". At present, the photographer has to buy two different bulbs for these two applications and change bulbs when the lighting requirements or the subject change.
With the present invention having two light sources displaced a certain distance apart, the lamp can be switched from Spot to Flood and back to Spot again electrically. Thus, a means is disclosed of electrically switching a bulb from "Flood" to "Spot" for maximum flexibility in photographic lighting.
The invention will now be described by way of example only with particular reference to the accompanying drawings, wherein:

Figure 1 is an illustrative view of a surgical light embodying the present invention in use.
Figure 1A is a view of a surgical light with a multi-filament lamp embodying the present invention.
Figure 2 is a side diagrammatic view of a cluster of multi-filament lights.
Figure 3 is a top view of the cluster of lights shown in Figure 2.
Figure 4 is a diagrammatic view of the lights of Figures 2 and 3 with the lamps energized to form a small pattern of light.
Figure 5 shows the lights of Figures 2 and 3 energized to form a large pattern of light.
Figure 6 is a schematic wiring diagram of an example of switching connections to the several filaments.

Now with more particular reference to the drawings, Fig. 1 shows surgical lights 110 and 110' supported by means of suitable arms on the ceiling of the hospital room to provide adjustment of the position of the light. A surgical table T is shown below the lights on which a patient may be supported which for purposes of illustration, will be considered to be the object on which the light patterns are to be projected.
The light switch panel D is supported at any convenient position on the wall near the surgical table where it will be readily accessible to the operator. The lamps in Lights 110 and 110' can be switched to energize all the filaments of the lamps of both Lights 110 and 110', or part of the filaments of each lamp to give a large light pattern, a small light pattern or any combination of large and small light patterns that may suit the particular requirements of the operator. The word surgical light is intended to include dental lamps and lights used in other areas of the health care field.
The surgical light 10 shown in Figure 1A has a housing 11 which may be supported on a suitable bracket. The housing 11 supports a first source reflector 12, a lamp 12', second reflector 13 and third reflector 14, the handle 17 is attached to the lamp housing by suitable structure.
Source reflector 12 has a focal point 20 and an axis of symmetry 42, which will be understood by those skilled in the art. The filaments which can be any suitable light sources will preferably be spaced from the focal point of reflector 12. The reflector 12,13, and 14 may have a plain reflecting surface, a diffusing type reflector surface or a faceted surface. Lamp 12' contains the first light source 15, the second 16 and could contain three or more light sources. Light source 15 and 16 could be made of any suitable material used for filaments or light generating elements familiar to those skilled in the art and will be referred to herein generally as filaments. The tungsten halogen material has been found to be a desirable type filament because of its compact size, approximating a point source with two or more filaments spaced a controlled distance from each other. It will be noted that the first light source 15 is spaced from the first reflector 12 between reflector 12 and focal point 20 and spaced from the second light source 16. The second filament 16 is shown spaced from the first filament 15 and the focal point 20.
The multi-filament lamp 12' may have a frosted glass envelope, to obtain patterns which are free of voids or shadows and preclude filament imaging at the pattern site. A clear lamp may also be employed in conjunction with faceted reflector 12 and/or variable stepped Fresnel lenses to provide the desired diffusion of light.
The handle 17 may be a removable, sterilizable handle of a type familiar to those skilled in the art which may be grasped by the hand of the operator to adjust the surgical light to the desired position.
When the first filament 15 of the surgical light of Figure 1A is energized, a typical light ray 26 will be reflected by reflectors 12, 13 and 14 through paths 27, 28 and 29 in a large pattern size onto an object. When second filament 16 is energized, the ray of light from the filament 16 may be reflected through paths 30, 31, 32 and 33 to give a smaller light pattern size on an object. Energizing other filaments could result in an intermediate pattern size, a smaller pattern size or a larger pattern size, thus by energizing the filaments 15 or 16, selectively different pattern sizes of light are obtainable.
In the embodiment of the invention shown in Figure 2 through 5, we show a surgical light 110 made up of light elements 111, 112, 113, 114,115 and 116 arranged in a circle and supported on frame 117 by brackets 118 supported on yoke 119 which may be attached to a suitable supporting surface such as a wall W or ceiling C above a surgical table T. The table T may support an object such as a patient P. Each of the lights 111 through 116 has a reflector 120. Reflectors 120 are concave and have a focal point 121 in accordance with good lighting practice. Lenses 122 are provided which may be frosted, clear or color corrected. Each of the light elements 111 through 116 has a lamp 121 which is shown by way of example as having a plurality of filaments 123, 124 and 125 spaced from each other and spaced from the focal point 126. Each of the light elements 111 through 116 could have two or more filaments and they are shown with these filaments by way of example only. The filaments 123 and 124 are spaced from the focal point and from the reflector a different distance along the axis of symmetry 142 and the reflectors 120 are so directed that when the filaments 124 are energized, the light is directed into a relatively small pattern 128 on the object T at a relatively high intensity. Only part of the filaments 124 need be energized when the small pattern size is desired because the pattern size being smaller only a portion of the light is required to result in the same pattern intensity.
When the filaments 123 of the lights are energized by closing switch S2, they direct light onto an object in a relatively large pattern, indicated at 127, and in order to provide a higher intensity pattern of light over the large pattern area 127, other filaments of lamps may be energized by closing switch S3 for example.
Any suitable number of light elements can be provided in the surgical light 110, and the light elements 111 through 116 can be supported in any practical configuration or any practical number of lights can be used, in any desired pattern each light in the array having several filaments and each light reflector aimed at the same area on an article on a surgical support, each of the light elements 111 through 116 being arranged about the axis of symmetry 142.
The lights can be used for flood lights, dental lights, photography lights or under application requiring variable focus or variable pattern size.
The dual filament lamp can be utilized in a multilamp arrangement with other single or multi filament lamps to provide pattern size variation from a large diameter flood effect to a smaller diameter spot effect. In addition, a combination flood/spot capability exists to provide large pattern exposure with secondary spot lighting simultaneously. In such a manner, large surface incisions can be lighted while also providing depth of illumination into smaller surgical cavities. Any variation from total flood or total spot to flood/spot combination can be performed by selective electrical energization of the proper filaments.

Claims

1. A filament type electric lamp (10) comprising:-

reflection means (12, 13, 14) including a first reflector (12) having a concave configuration with a focal point (20) and an axis of symmetry (42),

light source means including a first light source (15) and a second light source (16);

means supporting said first light source and said second light source on said axis of symmetry and at predetermined distances from said first reflector and in spaced relation to each other, one said light source being located closer to said first reflector than the other and in spaced relation to said first reflector and at least one of said light sources being supported at a predetermined distance from said focal point; and

means to selectively energize said first light source and said second light source; characterised in that said reflection means furthermore comprises a second reflector (13) and a third reflector (14); said first reflector (12) being disposed to direct light from said light source (15,16) to said second reflector (13), said second reflector (13) being disposed to direct light from said first reflector (12) to said third reflector (14), said third reflector (14) being disposed to direct light onto an object whereby a relatively small light pattern or a relatively large light pattern can be selectively directed onto said object by selectively energising said first or said second light source.

2. A lamp as claimed in Claim 1 wherein said light sources comprise tungsten halogen filaments.

3. A lamp as claimed in Claim 1 or 2 wherein the light source means includes three or more light sources.

4. A light source comprising a cluster of filament type electric lamps as claimed in any preceding claim.

5. A light source as claimed in Claim 4 having at least six said electric lamps disposed generally in a circle.