Abstract:
An operating room light fixture having a first lighting unit including a first light source and an external reflector, a second lighting unit including a second light source and an internal reflector, and a control unit. The second lighting unit is positioned in front of the first lighting unit with respect to the direction in which the light emerges from the light fixture. The control unit may be actuated by a rotary element located in a handle of the light fixture. A heat reflection filter may be provided for adjusting the color temperature of the light fixture to a desired value.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This application claims the benefit of priority under 35 U.S.C. § 119 of DE10 2004 055 839.6 filed Nov. 19, 2004, the entire contents of which are incorporated herein by reference. 
   FIELD OF THE INVENTION 
   The present invention pertains to an operating room light fixture with two lighting units in a lighting fixture housing. 
   BACKGROUND OF THE INVENTION 
   An operating room light fixture with two lighting units is known from DE 199 56 337 A1, in which a first lighting unit having a first light source and an external reflector is arranged after a second lighting unit having a second light source and an internal reflector in the direction in which the light emerges. The operating room light fixture has a control unit, which detects the failure of the first lighting unit and switches over to the second lighting unit as a function of a sensor signal. The first lighting unit acting as a main lighting unit is replaced now by the second light unit as a reserve lighting unit because of its defect. 
   An operating room light fixture with a light fixture housing, in which a lighting unit with a light source is arranged, is known from DE 101 19 215 A1. On the side facing the operating area, the light fixture housing has a handle, by means of which the operator (surgeon) can direct the lighting unit toward the area to be lit in the operating area. The operating room light fixture is fastened to a ceiling of the operating room by means of a suspension in an articulated manner. Operating elements are provided in a wall box fastened to a wall of the operating room for the remote operation of the operating room light fixture, the operating signals being transmitted to the operating room light fixture by means of a transmitter-receiver unit in a wireless manner. The drawback of the prior-art operating room light fixture is the relatively limited operating comfort. 
   SUMMARY OF THE INVENTION 
   The object of the present invention is therefore to provide an operating room light fixture in which better illumination of the operating area is guaranteed. 
   The object is obtained with an operating room light fixture with a first lighting unit having a first light source and an external reflector for generating a surface light and a second lighting unit arranged after the first lighting unit in the direction in which the light emerges. The second light source has an internal reflector for generating an additional in-depth illumination. A control unit is designed to connect the second lighting unit with variable luminous intensity to the first lighting unit. 
   According to the present invention, the first lighting unit with the first light source and with an external reflector associated with same and the second lighting unit with the second light source and with an internal reflector associated with same are provided. The first lighting unit is used to generate a surface light, while the second lighting unit is used to generate an additional in-depth illumination. As a result, the light advantageously does not have to be bundled to achieve in-depth illumination. A constant light field diameter is always obtained due to the combination of the lighting units The light sources and the reflectors of the lighting units are located on a common optical axis. 
   According to a variant of the present invention, the first light source of the first lighting unit and the second light source of the second lighting unit can be interconnected such that an optical variable is set according to a preset control curve between a minimum and a maximum by actuating the single operating element. 
   The special advantage of the device according to the present invention is that two lighting units can be actuated by means of a preset control mode such that illumination of the operating area corresponding to the needs is made possible. 
   According to a preferred embodiment of the device according to the present invention, the luminous intensity of the operating room light fixture is used as the actuating variable, so that adaptation of the luminous intensity is guaranteed with the combination of at least two lighting units. The in-depth illumination of the operating room light fixture can be optionally improved with the second lighting unit. 
   According to a variant of the device according to the present invention, the first and second lighting units are superimposed at least in one area of the control curve, which can be used especially to change the in-depth illumination. 
   According to a variant of the present invention, the operation of the lighting units can be performed by means of a central handle arranged on a side of the operating room light fixture facing the operating area to be lit or by means of a stationarily arranged wall-mounted control unit. The wall-mounted control unit may be connected with the control unit arranged in the light fixture housing of the operating room light fixture in a wireless manner or via a cable. 
   The operator can set two functions of the operating room light fixture simultaneously by actuating the operating room light fixture at one site. On the one hand, by grasping the handle, the operator can direct the operating room light fixture in space toward the operating area, so that improved illumination of the operating area is guaranteed. On the other hand, the operator can set or adjust the luminous intensity of the light source by operating the control element integrated in the handle, so that optimal illumination of the operating area can be performed relatively simply and rapidly. 
   According to a preferred embodiment of the present invention, the control element is designed as a rotary element, so that the luminous intensity of the light source can be adapted to the needs by rotation in an easy-to-operate manner. 
   According to a special embodiment of the present invention, the handle is designed as a sterilizable handle. The control element is advantageously arranged in a central handle, which has a sterile design and thus makes possible the independent operation of the light fixture by the sterile human operator. 
   According to a variant of the present invention, the control unit is arranged at the light fixture housing, so that the operation of the operating room light fixture, the actuating unit of the operating room light fixture and the lighting unit of the operating room light fixture are arranged in or at a common housing. As a result, the operating room light fixture has a compact design. 
   Provisions are made according to a variant of the present invention for arranging convergent lenses in the ray path between the light sources and the corresponding reflectors. It is especially advantageous in this connection to use as convergent lenses rotationally symmetrical, annular drum lenses, in the center of which the light source is accommodated. A circular focal cylinder with a plurality of focal points is generated by the drum lens. Especially homogeneous illumination of the operating area is achieved as a result. 
   According to a variant of the present invention, heat reflection filters are provided at the lighting units in the ray path between the light sources and the reflectors. The heat reflection filter at the second lighting unit, which contains a halogen lamp, additionally has a coating for converting the color temperature into a value in the range of 4,200 K. 
   An exemplary embodiment of the present invention will be explained in greater detail below on the basis of the drawings. 
   The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which a preferred embodiment of the invention is illustrated. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings: 
       FIG. 1  is a schematic vertical sectional view through an operating room light fixture according to the invention; 
       FIG. 2  is a block diagram of the operating room light fixture according to the invention; 
       FIG. 3  is a graphic view of a control curve for operating the operating room light fixture; 
       FIG. 4  is a longitudinal section of a drum lens according to the figure; and 
       FIG. 5  is a perspective view of the drum lens according to the figure. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring to the drawings in particular, an operating room light fixture  1  according to the present invention, which is used, for example, in operating rooms of hospitals, comprises essentially a light fixture housing  2 , in which a first lighting unit  3  and a second lighting unit  4  are arranged. The light fixture housing  2  is fastened to a ceiling of the operating room via a suspension, not shown, the adjustment in space of the light fixture housing  2  being guaranteed by pivot bearings of the suspension. 
   The first lighting unit  3  has a first light source  5  and an external reflector  6  associated with same. The second lighting unit  4  is arranged in front of the first lighting unit  3  in the direction  7  in which the light emerges and has a second light source  8  as well as an internal reflector  9  associated with same. 
   The first light source  5  and the second light source  8  are arranged on a common optical axis  10  of the operating room light fixture  1 . The first light source  5  is designed as a gas discharge lamp and generates a first light bundle  11  for forming a shadowless surface light with a relatively large-area external reflector  6 . The second light source  8  is designed as a halogen lamp and generates a second light bundle  12  for forming an additional in-depth illumination in cooperation with the relatively small-area internal reflector  9 . A drum lens  13  for guiding light as well as filters  14 ,  141 , which are arranged between the light sources  5 ,  8  and the reflectors  6 ,  9 , are associated with the light sources  5 ,  8 . The filters  14 ,  141  are used to absorb the infrared radiation. The filter  141  at the second lighting unit  4  additionally has a coating for converting the color temperature into a value in the range of 4,200 K, preferably 4,200±150 K. 
   A side  15  of the light fixture housing  2  on which the light emerges is formed essentially by a transparent glass pane. In a central area  16  of the side  15  on which the light emerges, a handle  17  projects downward in the direction  7  in which the light emerges from the side  15  on which the light emerges. The handle  17  is designed as a rotary element (control element) and is used to operate the first lighting unit  3  and the second lighting unit  4 . The handle  17  is mounted rotatably around an axis of rotation, which coincides with the optical axis  10 . The axis of rotation is directed in parallel to the direction  7  in which the light emerges. The handle  17  is connected with a relative incremental transducer  171 , which passes on an electric signal to a control unit  18  of the operating room light fixture  1 . A camera  19  may also be optionally installed in the handle  17 . The handle  17  is designed such that it can be sterilized and makes possible the direct operation of the lighting units  3 ,  4  by the operators (surgeon). As a result, direct adjustment (optical adjustment and adjustment in space) of the operating area by the operator is guaranteed. 
   The incremental transducer  171  may be designed as a stop-free transducer. The incremental transducer  171  may optionally have a mechanical lock for certain angle of rotation ranges. 
   The control unit  18  is preferably arranged at the light fixture housing  2 . As an alternative, it may also be arranged on a suspension, not shown. 
   As is apparent from  FIG. 2 , a power supply unit  20 , which is preferably fastened directly on the ceiling tube on a side of the suspension facing the ceiling of the operating room, is electrically connected with the control unit  18 . The power supply unit  20  makes possible the automatic switching of the power supply of the connected functional units from line-powered operation  21  to an emergency power generator  22  present in the building. 
   Moreover, the power supply unit  20  may be connected with a stationarily arranged control unit  23 . This control unit  23  is preferably fastened to a wall and is used to operate the lighting units  3  and  4  as well as to operate an additional indirect illuminating unit  24 , which is arranged on the suspension or on a top side of the light fixture housing  2 . This additional illuminating unit  24  generates a diffuse light in order to set a certain basic brightness in the operating room when the lighting units  3 ,  4  are switched off, without the surgical procedure being hindered. This additional illuminating unit  24  is used for indirect illumination for microinvasive surgery. 
   The control unit  23  is coupled with the power supply unit  20  via an electric line, which passes on the electric signals to the power supply unit  20  and the control unit  18  via sliding contacts in the hinges of the suspension without stops. The control unit  23  is thus used for nonsterile control just as the control by means of an interface  25  (RS-232 interface) integrated in the power supply unit  20 . This interface  25  may be arranged either at the ceiling tube or at an external switch box. It makes possible the coupling of a control unit, not shown, via a USB cable or in a wireless manner by means of infrared radiation. In addition, a wall-mounted control unit  33  may be provided for controlling the camera  19 . 
   The additional illuminating unit  24  can be actuated directly by the power supply unit  20 , wherein the first and second lighting units  3  and  4  can be actuated via the control unit  18 . The handle  17  is mechanically connected with the incremental transducer  171  and with the camera  19 . 
     FIG. 3  shows a control curve  26 , according to which the luminous intensity B delivered to the operating area is emitted by the operating room light fixture  1  as a function of an angle of rotation p of the handle  17 ,  171 . The control curve  26  is a total luminous intensity curve that has essentially a linear course and extends from a minimum  27 , which corresponds to the angle position φ=0° to a maximum  28 , which corresponds to an angle of rotation value of φ=90°. The total luminous intensity curve or control curve  26  is obtained from a superimposition of the first lighting unit  3  and the second lighting unit  4 , wherein only the first lighting unit  3  with its luminous intensity curve  29  contributes to the generation of the resulting total luminous intensity curve or control curve  26  in a first luminous intensity range in an angle of rotation range of φ between 0° and 45°, i.e., the second lighting unit  4  is switched off. The second lighting unit  4  is superimposed to the first lighting unit  3  in a second luminous intensity range, which extends in an angle of rotation range between φ=45° and φ=90°, the lighting unit  4  having a linear luminous intensity curve  30 , while the luminous intensity curve  29  of the first lighting unit  3  remains constant at 100%. The control curve  26  of the combined lighting units  3 ,  4  is expressed in kiloLux (kLx). The luminous intensity curves  29 ,  30  of the first lighting unit  3  and of the second lighting unit  4  are expressed as percentages relative to the nominal luminous intensity of the respective lighting unit  3 ,  4 . The luminous intensity curve  29  rises from 70% to 100% of the maximum luminous intensity in the first illumination range. As a result, the luminous intensity can be adjusted in the first illumination range between 80 kLx and 120 kLx. 
   The lighting units  3 ,  4  of the operating room light fixture  1  are controlled as follows: When the operating room light fixture  1  is switched on, the first lighting unit  3  has its maximum luminous intensity value L1. The second lighting unit  4  is switched off. The handle  17  assumes such a position that it corresponds to an angle of rotation of φ=45°. By rotating the handle  17  in a first direction, the luminous intensity  30  of the second lighting unit  4  can be superimposed to the luminous intensity  29  of the first lighting unit  3 , angle of rotation range 45° to 90° in  FIG. 3 . The maximum angle of rotation is 45°. The maximum  28  of the luminous intensity curve  26 , at which both lighting units  3  and  4  have reached 100% of their nominal luminous intensities (approx. 160 kLx), is reached in this position. 
   The handle  17  may be optionally rotated beyond the maximum angle of rotation of 45° in the first direction of rotation, for which case a mechanical lock is provided. Switching is performed in this case in a pure in-depth illumination mode, in which the first lighting unit  3  is dimmed to the extent possible or is switched off. 
   When the handle  17  is rotated in a second direction of rotation opposite the first direction after switching on the operating room light fixture  1 , the overall luminous intensity  26  is determined exclusively by the luminous intensity curve  29  of the first lighting unit  3 . The first lighting unit  3  is actuated in this first luminous intensity range such that starting from a switch-on angle 45°, the luminous intensity  29  is reduced in an angle range totaling 45° to approx. 70% of the nominal luminous intensity of the first lighting unit  3 . This corresponds to about 80 kLx, the minimum  27  of the total luminous intensity curve  26 . 
   A mechanical lock, which signals to the operator the switching on of the additional illuminating unit  24 , may be optionally provided during the further rotation of the handle  17  beyond the angle of rotation range of 45° in the first luminous intensity range. The first lighting unit  3  can be dimmed now, and the radiation from the light fixture housing  2  in the direction of the operating area is very extensively hindered. The illumination takes place in this state of switching essentially by the additional illuminating unit  24 . This can be brought about, for example, by moving up the first light source  5 , and the light is radiated upward by means of an auxiliary reflector. As an alternative, the emergence of the light radiation in the direction of the operating area can be hindered by covering the first lighting unit in the downward direction. 
   According to an alternative of the operating room light fixture  1 , not shown, the control unit  18  may also actuate the lighting units  3 ,  4  such that the first illumination range and the second illumination range comprise a different angle of rotation range or more than two illumination ranges are provided. The luminous intensity curves  29 ,  30  of the lighting units  3 ,  4  may also be combined such that a nonlinear course of the control curve  26  is obtained. For example, the control unit  18  may actuate the lighting units  3 ,  4  such that the second lighting unit  4  is switched on additionally already beginning from an angle of rotation φ at which the first lighting unit  3  has not yet reached its maximum nominal luminous intensity. 
   As an alternative, other optical variables of the lighting units  3 ,  4  may also be combined with one another. 
   As an alternative, the first lighting unit  3  and the second lighting unit  4  may also have light sources  5 ,  8  of the same type with equal or different nominal power. 
     FIG. 4  shows the longitudinal section of the drum lens  13 . The drum lens  13  has an internal diameter of 40 mm, an external diameter of 80 mm and a height of 50 mm. 
   A perspective view of the drum lens  13  is shown in  FIG. 5 . 
   While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.