Abstract:
An operating lamp includes a plurality of illumination elements arranged in discrete groups. The illumination elements include at least one white illumination element, adapted to emit a white light, and multiple colored illumination elements, each adapted to emit a non-white, colored light. The operating lamp also includes a controller in communication with the illumination elements, and one or more storage devices configured to communicate with the controller. Each of the storage devices is associated with one or more of the groups of illumination elements, and each of the storage devices contains a set of power values for each associated group. The controller is configured to control illumination of each group of illumination elements individually, based on the associated power values.

Description:
RELATED APPLICATION 
     Under 35 U.S.C. §119, this application claims the benefit of a foreign priority application filed in Europe, serial number EP 05 024 819.4, filed Nov. 14, 2005, the entire contents of which are hereby incorporated by reference. 
     TECHNICAL FIELD 
     This disclosure relates to controlled illumination of an operating lamp, e.g., for illuminating an operating area. 
     BACKGROUND 
     Control of a luminous flux of an operating lamp with respect to color temperature, intensity and distribution over a light emitting surface can be realized with operating lamps having conventional illumination means, such as halogen or gas discharge lamps. A color temperature of halogen or gas discharge illumination means can be adjusted, for example, using filter techniques. The color temperature can also be changed when several illumination means are used. Brightness can be adjusted using apertures, e.g., without changing the color temperature. With electric dimming, a change in brightness can also change the color temperature. In addition, distribution of the luminous flux over a light emitting surface can be changed through aperture techniques and/or with the use of several illumination means. 
     It is desired to improve activating of illumination means of an operating lamp with respect to adjustment of a color temperature and an intensity (brightness) of the operating lamp. 
     SUMMARY 
     According to one aspect, individual illumination means (i.e., illumination elements) are combined into groups. Power values, which are allocated with the groups, are stored (e.g., on a corresponding storage device) so that a controller can drive these groups separately. 
     A color temperature and intensity (brightness) of operating lamps can be adjustable. Towards this end, light emitting diodes (LEDs) of different colors (e.g., cold white, warm white, cyan, blue) can be used as illumination elements. The illumination elements, and/or individual groups of the illumination elements, can then be driven by adjustable power values (e.g., current and/or voltage). In order to standardize illumination parameters for individual groups of the illumination elements, power values for different illumination parameters are stored for each group. 
     A color temperature of the operating lamp, a light intensity of the operating lamp and/or a distribution of the light intensity across a light emitting surface of the operating lamp can be taken into consideration as nominal values for the illumination parameters. The groups of illumination elements can be driven, controlled and calibrated using the nominal values. 
     A current strength can be used as a power value or luminous flux value. The current strength can be controlled by the nominal values. A current value can be used to control the current strength. Alternatively or additionally, the current value can be a pulse sequence for pulse width modulation. The illumination elements can be combined into one or more modules or combinations. This provides the possibility to design different operating lamps. 
     Each module or each combination can include a corresponding storage device (e.g., an EPROM). Moreover, data transfer to a central controller of the operating lamp can be provided. This can help to facilitate exchange of modules for repair work. For example, by storing the data for each nodule, a replacement module can be installed which has the same lighting properties. Even after replacement of the central controller, operation of the lamp with its calibrated values is ensured. 
     The details of one or more embodiments of the invention are set fourth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  shows an embodiment of a light module for an operating lamp. 
         FIG. 2  shows one embodiment of an operating lamp. 
         FIG. 3  shows an operating field of an operating element (i.e., user interface) for the operating lamp of  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION 
     As shown in  FIG. 1 , an individual light module  6   a  can include a housing  9  having mechanical and/or electric or electronic connecting elements or connectors, e.g., for connecting the module to neighboring light modules. The shape of the light module is designed such that a plurality of the modules can be disposed on a curved (e.g., spherical) surface. For example, in some embodiments a plurality of the modules are disposed on a surface having a radius of 1000 mm without substantial gaps between adjacent modules. Towards this end, the light modules can have a hexagonal shape, such that, when assembled, a type of honeycomb or facette structure is formed. The surface of the light modules need not necessary be flat, but may be slightly concave to improve reproduction of the curvature of the spherical surface, and an optical axis of the light module  6   a  can face a focus of the spherical surface. 
     Different light field shapes can be generated by combining light from adjacent modules oriented at different angles of incidence. Intermediate elements can also be used in this connection. Multiple (e.g., 10, 20, 30, 40, 50 or more) LEDs can be uniformly distributed, in the light module  6   a , of which only three (i.e.,  10   a - 10   c ) are shown in  FIG. 1 . Formation of shadows is optimized through planar emission of light from the LEDs  10   a - 10   c . Toward this end, each of the nearly point source LEDs  10   a - 10   c  can be associate with suitable optical elements (e.g., lenses  11   a - c ), such that light beams  12   a - c  are emitted from the LEDs  10   a - c , respectively. The shape of the optical elements  11   a - c  is designed such that they fill the light module  6   a  up to the edge thereof. The lens elements  11   a - c  can also have a scattering structure to render the illumination field more homogeneous. The lower side  5  of the light module  6   a  can be covered by a transparent plate. 
     The combination of individual light modules  6   a - 6   e , as shown in  FIG. 2 , can form a light source having various color temperatures, for example, approximately 4500 K, and a color reproduction index Ra of greater than about 93 to obtain natural color representation of an illuminated object (e.g., tissue to be operated on). For this reason, LEDs (e.g., LEDs  10   b  and  10   c ) that generate colored (i.e., non-white) light are used in combination with white-light LEDs (e.g., LED  10   a ). The addition of colored light, such as cyan and blue, can help to minimize a spectral breakdown that can occur when only white-light LEDs are used. Moreover, specific color mixtures can be generated to improve the vision of the operating surgeon. With a constant brightness of the white LEDs in the light source, the color temperature and color reproduction of the mixed light, which is generated by the overall light source, consisting of all individual light modules  6   a - 6   e  can be variably adjusted. The luminous flux intensity of the LEDs  10   a  through  10   c  can be continuously changed by selectively dimming the intensity of the colored LEDs  10   b  and  10   c . The overall illumination strength can also be kept constant through matched intensity control of all LEDs. The LEDs  10   a - c  can be connected to a central controller  15  through current lines  13   a - c  and printed board  14 . This interconnect between the LEDs and the controller allows for electric dimming of the luminous flux of the LEDs, which can be selectively operated, e.g., through an operating element  16 . 
     As shown in  FIG. 2 , a variably controlled operating lamp  1  can include a plurality of individual light modules  6   a - 6   e , e.g., three or five or more. Each individual light module can include a plurality of (e.g., 35 or more) illumination elements (e.g., LEDs) of different colors. For example, in some cases, each individual LED, including its optical system, is able to illuminate the entire illumination field, and consequently also each individual light module  6   a - 6   e . Different light intensities and/or color temperatures of the operating lamp can be adjusted, for example, by activating the LEDs in different ways. Thus, the individual light modules can be adjusted to achieve substantially identical optical effects, such as brightness and color temperature. 
     The LEDs can be combined into groups, wherein each group can be individually driven. The LEDs can be grouped, for example, according to color and, when the maximum current carrying capacity of the controller  15  has been exceeded, the number of LEDs. The individual groups can be combined in modules or other combinations. The groups can then be driven through the central controller  15  allowing a user can select a desired color temperature, light intensity, and/or distribution of the emitted light. The light intensity and/or color temperature of each module  6   a - 6   e , or each combination of individual groups of LEDs, can be measured and calibrated to corresponding nominal values. This can also compensate for changes in the color temperature of the LEDs that occurs as result of dimming, i.e., as a result of a reduced current flow (linear current control). Calibration can also be used to compensate for variances in color temperature and light intensity, which can occur as a result of production tolerances of LEDs. Specifically, the power values for the individual groups can be measured and adjusted to achieve the nominal values. The resulting power values (i.e., the power values for reaching the nominal values)—are stored for the module  6   a - e  or the combination of individual groups. The power values correspond to the power at which each individual group can be driven in order to reach the set nominal values. This power value can be a current value (linear current control) or a pulse sequence for pulse width modulation for the supply current of the LEDs. The combination of the setting for the individual groups then yields the desired settings for the nominal values of color temperature, intensity and distribution. It is also possible not to store the power values but to measure the color temperature and intensity of the emitted light during operation and control the parameters therewith. The power values can be stored in the central controller  15 . The power values can also be stored on individual storage devices  24  associated with corresponding module  6   a - 6   e  or combination of groups. This may be realized, e.g., on the printed board  14  in the module  6   a - 6   e , on which the plug connector is disposed to distribute the electric supply. For example, a dedicated storage component  24  ( FIG. 1 ), e.g., an EEPROM (electrically erasable programmable read-only memory) or a flash memory can be allocated to each module  6   a - 6   e  or combination of groups. When the operating lamp  1  is started, these values are transferred to the central controller  15  and the module  6   a - 6   e  or the combination is operated with the corresponding calibrated values. 
     Each module  6   a - 6   e  can also include a temperature sensor  26  to measure a temperature in the housing  9  and to reduce the light intensity in the event that the temperature is above a predetermined threshold temperature, thereby reducing the temperature. 
     A basic setting of a color temperature of 4500 K can be predetermined for the operating lamp  1  and automatically generated when the operating lamp  1  is switched on. Other desired color temperatures, depending on the application of the operating lamp  1 , can be adjusted through the operating element  16  (e.g., control panel or user interface). The operating element  16  of  FIG. 3  has a removable key/rotational switch  17 , which can be sterilized. The switch  17  is actuated to send pulses to the controller for selecting different operating states and/or operating parameters. For example, the different operating states (outlined below) are sequentially switched through by pressing the switch  17 :
         on/off (complete switch-off or standby state)   light intensity (brightness)   color temperature   illumination situation (selection of the intensity distribution of the emitted light)   optional: camera drive (orientation, zoom)       

     Defined progressive rotation of the switch  17  is facilitated by latching positions. This changes the operating parameters (outline below) within the operating states. The different operating states and operating parameters can be displayed on the operating element  16 . The following parameters are stored in the controller  15 :
     Light intensity: e.g. endo (10%)/50%/60%/70%/80%/90%/100%   Color temperature: e.g. 3500 K/4000 K/4500 K/5000 K   Illumination situation: e.g. 1 operating surgeon/2 operating surgeons/large-surface wound/deep narrow wound   

     When the sterile switch  17  is switched off or on, the standby mode is activated or deactivated. The operating parameters are stored during switching off, and may be further displayed. When the operating lamp  1  is switched on, it assumes the operating state of the last stored parameters. The operating element  16  can include, in addition to the switch  17 , a further switch  18  for completely switching the operating lamp on or off. When the operating lamp is switched on, it is in a state of predefined parameters (basic position). As shown in  FIG. 3 , the operating element  16  can include a display  19  with several LEDs for displaying the intensity of the adjusted brightness of the operating lamp  1 , a display  20  with several LEDs for displaying the intensity of the adjusted color temperature, a display  21  for displaying the adjustment of the operating lamp  1  for deep or shallow wounds, and a display  22  for displaying the adjustment of the operating lamp  1  for one ore more operating surgeons within the light field. 
     Activating can be performed, e.g., as follows: 
     
       
         
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
               
               
               
             
           
               
                   
               
               
                 Situation 
                 Color 
                 Illumination 
                 Module l 
                   
                 Module n 
               
             
          
           
               
                 (distribution) 
                 temperature 
                 intensity 
                 ww 
                 kw 
                 bl 
                 cn 
                 . . . 
                 ww 
                 kw 
                 bl 
                 cn 
               
               
                   
               
             
          
           
               
                 S1 
                 3500 K 
                  50% 
                 60 
                 20 
                 0 
                 0 
                 . . . 
                 59 
                 22 
                 0 
                 0 
               
               
                 S1 
                 4000 K 
                  50% 
                 55 
                 25 
                 20 
                 20 
                 . . . 
                 53 
                 27 
                 22 
                 19 
               
               
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 . . . 
                 — 
                 — 
                 — 
                 — 
               
               
                 S1 
                 5500 K 
                 100% 
                 95 
                 98 
                 85 
                 83 
                 . . . 
                 96 
                 99 
                 83 
                 84 
               
               
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 . . . 
                 — 
                 — 
                 — 
                 — 
               
               
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 . . . 
                 — 
                 — 
                 — 
                 — 
               
               
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 . . . 
                 — 
                 — 
                 — 
                 — 
               
               
                 S4 
                 5500 K 
                 100% 
                 102 
                 85 
                 80 
                 78 
                 . . . 
                 0 
                 0 
                 0 
                 0 
               
               
                   
               
               
                 Ww = warm white 
               
               
                 Kw = cold white 
               
               
                 Bl = blue 
               
               
                 Cn = cyan