Abstract:
An operating light ( 36 ) and a process are provided for lighting an operating table via an operating light ( 36 ). The operating light ( 36 ) includes at least one first radiation source ( 1 ), which is suitable for producing light ( 12 ) with locally different, especially radially outwardly decreasing color temperature distribution ( 18 ) in a plane extending at right angles to the work area.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of priority under 35 U.S.C. §119 of German Patent Application DE 10 2010 050 300.2 filed Nov. 3, 2010, the entire contents of which are incorporated herein by reference. 
       FIELD OF THE INVENTION 
       [0002]    The present invention pertains to an operating light and to a process for lighting an operating table by means of an operating light. 
       BACKGROUND OF THE INVENTION 
       [0003]    It is known that light-emitting diodes (LEDs) are used as a radiation-emitting component in many different fields of applications of novel light sources in order to benefit from the longer service life and better energy efficiency compared with conventional lighting means. Thus, examination or operating lights increasingly use LED technology, especially white LEDs. White LEDs may be composed of a blue-emitting semiconductor, which is coated with a phosphor layer, which absorbs part of the transmitting blue light, fluoresces broad-band yellow light and thus generates white light by mixing the radiation. 
         [0004]    In addition, some basic properties of operating lights, e.g., the color temperature or light color, which must be met by operating lights, are specified in International Standard IEC 60601-2-41 entitled “Medical Electrical Equipment—Part 2-41: Particular requirements for the basic safety and essential performance of surgical luminaires and luminaires for diagnosis”. 
         [0005]    Thus, a color temperature of 3,000 K-6,700 K is specified within a “color hexagon” close to the black body line for operating lights according to this standard specification. A light color temperature of about 4,500 K is established for operating lights (similar to direct sunlight). 
         [0006]    The LED technology in operating lights makes it possible to directly set a color temperature (Correlated Color Temperature (CCT)) of the white light, e.g., by setting the properties of the phosphor material and setting the absorption length over the layer thickness of the phosphor material, for example, with monochromatic white LED with a color temperature of 4,500 K. As an alternative, this can likewise be achieved with different colored LEDs or different white LEDs. Light is mixed here to white at the site of the focus. An adjustable color temperature is likewise possible in operating lights of the LED configuration mentioned in the alternative, and this is set mostly according to personal preference. 
         [0007]    An operating light with a plurality of LED lighting means is known from EP 1568936 A1, wherein some LEDs are designed to produce colored light and other LEDs are designed to produce white light and means for setting the intensity of the colored LEDs are provided. Furthermore, a process for lighting an operating site with an operating light comprising white or colored LEDs is described, wherein the intensity of the colored LEDs is adjustable. 
         [0008]    An operating light with a light body for receiving lighting means is described in EP 1568934 A1, wherein a light source in the center of the light body can be actuated independently from other lighting means. 
         [0009]    WO 2003/019072 A1 shows a conventional white light-emitting diode, which is used to set a color temperature and a color rendering property. The white light-emitting diode sets the color temperature, and a monochromatic correcting light-emitting diode is used to change the color rendering by color mixing. 
         [0010]    WO 2007/014769 A1 shows an operating light with at least one light source arranged in a light body and with an optical means. To direct the visible radiation of the light source in a main light emission direction onto a field of operation, the operating light has an auxiliary lighting means, which can be switched independently from the light source. 
         [0011]    An operating light, which has an optical imaging system and at least one lighting element with at least two light sources, wherein the light sources emit emissions of different spectra, is known from EP 1985912 A1. The light sources are arranged close to the optical axis of the lighting element, so that the emissions are superimposed even before they reach a reflector. 
         [0012]    It is known that light with a large blue component (white light with a higher color temperature above 4,000 K, also called cold white or neutral white) enhances the ability to concentrate and reduces fatigue. However, this light is often felt to be too glaring and cold. Light with a large red component (lower color temperature below 4,000 K, warm white) is, by contrast, helpful for relaxing and relieves stress. 
       SUMMARY OF THE INVENTION 
       [0013]    The object of the present invention is therefore to provide an operating light or a process for lighting an operating table by means of a corresponding operating light, which operating light or process leads to a further improvement of light perception compared with the lighting means known from the state of the art. 
         [0014]    According to the invention, an operating light is provided with at least one first radiation source, which radiation source is suitable for producing light with a locally different color temperature distribution in a plane extending at right angles to a work area in the work area. The local color temperature distribution in the plane extending at right angles to the work area has an especially radial, outwardly dropping pattern with a plurality of especially radial areas of nearly constant or continuously changing, especially slightly decreasing color temperature. In a first area, which covers the innermost part of the work area, the color temperature is nearly constant and has a mean value between 4,500 K and 6,700 K, preferably between 5,200 K and 6,000 K and especially 5,400 K. In a second area, which adjoins the first area, the color temperature decreases from the inside to the outside. In a third area, which adjoins the second area, the mean value of the color temperature is between 3,000 K and 4,000 K, preferably between 3,200 K and 3,900 K and especially 3,500 K. 
         [0015]    According to another aspect of the invention, a process is provided for lighting an operating table by means of an operating light. The process comprises providing a radiation source and producing light with the radiation source. The light has a locally different color temperature distribution in a work area, in a plane extending at right angles to the work area, wherein the locally color temperature distribution has a radially outwardly dropping pattern with a plurality of radial areas of at least one of nearly constant, continuously changing and slightly decreasing color temperature. The plurality of radial areas include a first area which covers an innermost part of the work area having a color temperature that is nearly constant and has a mean value between 4,500 K and 6,700 K, a second area, which adjoins the first area, the second area having a color temperature that decreases from an inside of the second area to an outside of the second area and a third area, which adjoins the second area, the third area having a mean color temperature value between 3,000 K and 4,000 K. 
         [0016]    The operating light with at least one first radiation source is suitable for producing light with a locally different color temperature distribution in a plane extending at right angles to a work area in the work area; wherein
       the local color temperature distribution in the plane extending at right angles to the work area has an especially radial, outwardly decreasing pattern with a plurality of especially radial areas of nearly constant or continuously varied color temperature;   in a first area, which covers the innermost part of the work area, the color temperature is nearly constant and decreases slightly and has a mean value between 4,500 K and 6,700 K and preferably between 5,200 K and 6,000 K, and especially equals 5,400 K;   in a second area, which adjoins the first area, the color temperature decreases from the inside to the outside; and   in a third area, which adjoins the second area, the mean value of the color temperature is between 3,000 K and 4,000 K, preferably between 3,200 K and 3,700 K and especially equals 3,500 K.       
 
         [0021]    The local color temperature distribution has, in a plane extending at right angles to the work area or to the beam axis, a radial pattern and forms a plurality of radial areas with nearly constant or continuously varied color temperature. 
         [0022]    “Nearly constant” means, in connection with the present invention, that the color temperature may undergo a slight change in the first area, especially, e.g., a decrease in the color temperature from the center to the outer edge of the area by less than 10%, preferably less than 5%, more preferably less than 2% and especially less than 1% in the first area. 
         [0023]    In preferred embodiments, the color temperature changes by 600 K or less in the first area. The mean value of the color temperature in the first area preferably equals 5,400 K. 
         [0024]    The color temperature preferably decreases in the second area by 1,000 K or more. The color temperature changes by preferably 600 K or less in the third area. The mean value of the color temperature in the third area preferably equals 3,500 K. 
         [0025]    The first area preferably covers the working position within the work area, and the lighting intensity within the first area is greater than outside the first area. 
         [0026]    In one embodiment, the size of the first area is determined by a first external diameter, at which the lighting intensity has dropped to 80% to 20% of the maximum thereof and preferably to 65% to 35% of the maximum thereof or to 50% of the maximum thereof. The size of the second area is determined by a second external diameter, at which the lighting intensity has dropped to 15% to 5% of the maximum thereof and preferably to 10% of the maximum thereof. 
         [0027]    The pattern of the lighting intensity of the light is selected in a section at right angles to the beam axis within the work area to be such that the ratio of the diameter at 50% of the intensity to the diameter at 10% of the intensity is at least 0.5, this ratio being independent from the pattern of the color temperature. 
         [0028]    In an exemplary embodiment, the radiation source comprises an LED chip with a phosphor converter, which is applied in front of the chip in the emission direction and is larger than the chip, so that light with different color temperatures can be emitted locally and in a direction-dependent manner. 
         [0029]    In a variant of this embodiment, the radiation source comprises an optical system for bundling and imaging the light radiation. The optical system is designed such that the local color temperature characteristic is preserved. 
         [0030]    In another embodiment, the operating light comprises a plurality of different radiation sources, wherein homogeneous color temperatures of the radiation sources are superimposed to the local color temperature pattern by means of different focus diameters. 
         [0031]    In another embodiment, the operating light comprises a plurality of radiation sources of the same type, wherein the radiation sources comprising a plurality of LED lens pairs with radial color temperature pattern are oriented toward a light spot at a defined working distance. 
         [0032]    In another embodiment, the operating light comprises a plurality of radiation sources with different lighting means. The different lighting means comprise halogen lights, gas discharge lights or LEDs. 
         [0033]    In another embodiment, the radiation sources have a light filter and reflector of their own, which are arranged in a light body one after another and both produce a light spot each with different, homogeneous color temperatures and different focus diameters on a common axis at the same working distance. The reflector may also be split. 
         [0034]    At least one first radiation source, which is suitable for producing light with a local color temperature distribution in a work area in a plane extending at right angles to the beam axis or to the axis of the light, is made available in the process according to the present invention for lighting an operating table by means of an operating light. 
         [0035]    In one embodiment of the process, a light spot with a radial color temperature pattern is produced, which has a constant color temperature pattern in a first area, and has a color temperature decreasing towards the edge of the light spot, wherein the color temperature pattern is preset such that more fatigue-free working is made possible during the operation of the operating light, and a physiological light perception is utilized by the central operating site being lit with higher color temperature in order to make possible high concentration and less fatigue, and a lower color temperature is provided at the edge or outside the central operating site in order to create a quieter picture with less overstimulation. 
         [0036]    The present invention is explained in more detail below on the basis of exemplary embodiments with reference to the attached figures. 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 preferred embodiments of the invention are illustrated. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0037]    In the drawings: 
           [0038]      FIG. 1  is a cross-sectional view showing a radiation source with an optical system as components of an operating light according to the present invention; 
           [0039]      FIG. 2  is a cross-sectional view showing the radiation source from  FIG. 1 ; 
           [0040]      FIG. 3  is a schematic top view showing an intensity profile of the radiation source from  FIG. 1 ; 
           [0041]      FIG. 4  is a sectional view showing an operating light according to the present invention according to  FIGS. 1 through 3 ; 
           [0042]      FIG. 5   a  is a diagram concerning the radiation characteristic of the operating light according to  FIG. 4 ; 
           [0043]      FIG. 5   b  is another diagram concerning the radiation characteristic of the operating light according to  FIG. 4 ; 
           [0044]      FIG. 5   c  is another diagram concerning the radiation characteristic of the operating light according to  FIG. 4 ; 
           [0045]      FIG. 6  is a schematic view showing an intensity profile of the operating light according to  FIG. 4 ; 
           [0046]      FIG. 7  is a cross-sectional view showing the optical system from  FIG. 1 ; 
           [0047]      FIG. 8  is a cross-sectional view showing another radiation source with optical system as components of an operating light according to the present invention; 
           [0048]      FIG. 9  is a cross-sectional view showing another operating light according to the present invention; 
           [0049]      FIG. 10  is a schematic view showing an arrangement of light sources for producing a suitable CCT radiation distribution; 
           [0050]      FIG. 11  is a cross-sectional view showing another operating light according to the present invention; 
           [0051]      FIG. 12   a  is a schematic cross-sectional view showing another operating light according to the present invention; 
           [0052]      FIG. 12   b  is a schematic cross-sectional view showing another operating light according to the present invention at a right angle with respect to the cross-section of  FIG. 12   a;    
           [0053]      FIG. 13  is a schematic intensity profile of the operating light according to  FIGS. 12   a  and  12   b.    
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0054]    Referring to the drawings in particular,  FIG. 1  shows a radiation source with an optical system as a component of an operating light according to the present invention in a cross-sectional view, as it is used, for example, in operating rooms of hospitals. The radiation source  1  comprises an LED  2  and the optical system  3 , wherein the optical system  3  is arranged on a radiation-emitting side of LED  2 . The orientation of LED  2  to optical system  3  can be achieved by fastening on a printed circuit board  4  by means of a base  8 , for example, by soldering. The printed circuit board  4  also guarantees the power supply of LED  2  via contact tabs  9 . 
         [0055]    As is shown in  FIG. 2 , light source  1  comprises LED  2  emitting white light with a blue-emitting chip  5 . A phosphor converting into “yellow” light, which is designed as a phosphor layer  6  here, is applied on the radiation-emitting side of LED  2 . Furthermore, a primary lens  7  is provided, which increases the uncoupling efficiency. The area of phosphor layer  6  is larger in the embodiment according to  FIG. 2  than that of chip  5 . For example, an area of approximately 1 mm 2  may be selected for chip  5  of LED  2  and the area of the phosphor layer  6  may equal 2 mm 2  in this example. The LED  2  used is, for example, the neutral white light-emitting diode P 4 , which is manufactured by Seoul Semiconductor. 
         [0056]    The blue light emitted by chip  5  of LED  2  radiates through the phosphor layer  6 . “Yellow” light, which mixes with blue light into white, fluoresces in phosphor layer  6 . The path length of the blue light through phosphor layer  6  is longer at the edge of phosphor layer  6 , so that more blue light is converted into “yellow” light. Consequently, the blue/yellow light mixing ratio is shifted compared to the center, and a white light with a varied color temperature, i.e., with a lower color temperature in this case, is formed. 
         [0057]    The phosphor layer  6  is coordinated here such that the color rendering is very high in all color ranges, which is characterized by a color rending index (CRI) higher than 85. 
         [0058]    As a result, a combined light emitter is formed from the chip plus the phosphor layer located in front of it with a quasi-rectangular radial color temperature profile, which is schematically shown in  FIG. 3 . Light with a color temperature of approximately 5,300 K is emitted in the inner area  10 . The color temperature equals 3,600 K in the outer area  11 . 
         [0059]    Such a light source is not usually desired for lighting applications, because a homogeneous color temperature distribution is necessary for many such applications. However, it is advantageous in this case, especially if the emitted light is imaged through the optical system  3  while maintaining the local color temperature distribution, as is explained below. 
         [0060]    The light source  1  produces light emission  12 , which produces, at a working distance  13  of about 1 m, centered around a light source axis  20 , on a working surface  14 , a light spot  24  with a first diameter  16  of about 20 cm (typically 10 cm to 40 cm) and with a second diameter  15  of about 10 cm (typically 5 cm to 20 cm), as it is shown in  FIG. 4 . The first diameter  16  is characterized by a drop in intensity to about 10% of the central light intensity. The second diameter  15  is characterized by a drop in intensity to about 50% of the central light intensity. The intensity pattern of the light spot  24  on the working surface  14  is schematically shown in the diagram in  FIG. 5   a.    
         [0061]    The light source  1  produces the light spot  24  with an outwardly decreasing color temperature, as it is shown in  FIG. 5   b  and  FIG. 6 . Three color temperature areas  21 ,  22 ,  23  are formed now. The first area  23  is located in the center of the light spot  24  and has a diameter of about 10 cm and has a high color temperature CCT 1  with a mean value of 5,400 K in the center; the decrease in color temperature in this area is small and does not exceed 70 K in this diagram ( FIG. 5   b ). In a second, middle area  21 , the color temperature decreases by more than 1,000 K, for example, to a diameter of 20 cm. There is a nearly constant, but nevertheless slightly decreasing color temperature CCT 2  of at least 3,600 K in a third, outer area  22 , which adjoins the second area  21  outside of 20 cm. 
         [0062]    The intensity distribution of the light source is illustrated in  FIG. 5   a . In the first area  23 , the lighting intensity is higher than 50% of the maximum lighting intensity in the center of the radiation and increases towards the center. The lighting intensity decreases greatly in the second area, which adjoins the first area, but it is still always more than 10% of the maximum lighting intensity, even towards the outer edge of the area. The lighting intensity decreases further to a value of zero in the outermost area  22 . 
         [0063]    The light source produces light that has a high color rendering (CRI&gt;85), as is shown in  FIG. 5   c , over the entire areas  21 ,  22 ,  23 , i.e., up to a diameter of about 25 cm. 
         [0064]    Optical system  3  of light source  1  for LED  2  is shown in more detail in  FIG. 7 . Optical system  3  is a combination of refractive and reflecting optical elements. It is calculated numerically for the special requirement imposed on an operating light and the desired light distribution and is manufactured according to the injection molding process, for example, from plastic such as polymethyl methacrylate (PMMA). Reflection is used in the outer area  33  of optical system  3  in the form of total internal reflection on a surface  34 , and refraction is used in the inner area  32  on two surfaces to form a light beam. Optical system  3  has a reflective aspherical total internal reflection (TIR) surface  27 . Moreover, optical system  3  has areas  35  for mechanical fixation, whose surfaces  30 ,  31  do not have any optical function. 
         [0065]    According to the requirements imposed on operating lights, the light  12  of the light sources  1  has a light spot diameter  16  of about 20 cm (at 10% intensity) at a working distance  13  of about 1 m. 
         [0066]    Efforts are usually made in designing the optical system to make do without imaging properties for optimizing the surfaces of an LED optical system for collimating the light emission of the LED in order to homogenize the color temperature patterns of LED  2  and to compensate or make invisible source details, e.g., bond wires, rectangular surfaces, inhomogeneous color temperature and brightness distribution. However, LEDs with homogeneous distribution of intensity and/or color temperature are usually used to optimally compensate inequalities to the extent possible. 
         [0067]    Difference in the invention being described: Instead of using an LED with the greatest possible homogeneity of intensity and color temperature pattern, an optical system is selected here which comprises collimation with imaging properties of the light source  1  at the working distance  13  in order to obtain a locally resolved radiation characteristic of the LED. An LED  2  with the most inhomogeneous color distribution possible supports the design. The geometric details of the source (bond wires, rectangular shape) are effaced and become invisible due to superimpositions of the lights of many light sources with different directions. However, the fact that the many sources are placed one over the other does not cause any change in the color temperature and brightness distribution ( FIGS. 5   a ,  5   b ,  5   c  and  FIG. 6 ) of an individual source. 
         [0068]    Furthermore, optical system  3  is constructed such that the lighting intensity profile at the working site drops to 50% of the central lighting intensity at the diameter of about 10 cm. At the same time, optical system  3  ensures that an intensity profile meeting the guidelines for an operating light (EN 60601-2-41), i.e., the ratio of the diameter at 50% of the intensity to the diameter at 10% of the intensity equals &gt;0.5, this ratio being independent from the changes in color temperature, is generated at the imaging site. 
         [0069]    To obtain the desired lighting intensity of an operating light, a plurality of radiation sources with LED  2  and optical system  3  are typically used as a light source, as it is shown in  FIG. 9 . Many of the color-optimized light sources  1  with LED  2  and optical system  3  are used here, and their light  12  is imaged as a superimposed light radiation  37  to a light spot  24 , which does, however, again have the desired color temperature and intensity profile, as is described in Figures  FIGS. 5   a ,  5   b ,  5   c  and  6 . The transition  21  between the two areas of nearly constant color temperature  22 ,  23  becomes somewhat less sharp than in case of an LED/optical system light source only due to manufacturing tolerances. 
         [0070]    For example, an embodiment of operating light  36 , which is equipped with 66 light sources  1  comprising LED  2  and optical system  3 , is shown in  FIG. 9 . The light sources  1  are oriented such that the superimposed light  37  from each LED/optical system of light source  1  is superimposed on the axis  20 ′ of the combined light sources at the working distance  13  of the operating light  36 . 
         [0071]    It is also possible to use only one LED with a suitable optical system in case of LEDs with a very high light intensity (e.g., &gt;1,000 μm). It is likewise possible to use, instead of an LED  2  with a small chip  5  and a larger phosphor layer  6 , an array of a plurality of LED chips  39  with low color temperature and selected intensities around a central LED  38  with a high color temperature, as it is shown in  FIG. 10 . Accordingly, a color temperature distribution  18 , a lighting intensity pattern  17  and a color rendering pattern  19  are produced in the light spot  24 , which corresponds to those according to  FIGS. 5   a ,  5   b ,  5   c  and  FIG. 6 . 
         [0072]      FIG. 11  shows as another exemplary embodiment an array of a combined light source  40  with two light sources  1 ′ and  1 ″, which comprise two LEDs  2 ′ and  2 ″ each and two optical systems  3 ′ and  3 ″ each. As an alternative, one of the two light sources  1 ′ or  1 ″ may also have another lighting means and/or optical system. 
         [0073]    It is likewise possible to use two light sources  1 ′ and 1″, which are oriented in relation to one another on a mechanical fixing means  41 , multiply with different color temperatures and different light spot diameters  16 ′ and  16 ″ of, e.g., 15 cm and 25 cm, respectively. The light radiation of the light sources  1 ′ and  1 ″ is superimposed at the working distance  13  in order to produce a light spot  24 ′. 
         [0074]    Consequently, a color temperature area  23 ′, which is formed from the mixture of light radiations  12 ′ and  12 ″ of the two light sources  1 ′ and 1″ with high color temperature, is obtained centrally. In the edge area, i.e., at a diameter of, e.g., 15 cm to 20 cm or greater, a color temperature area  22 ′ with a low color temperature is formed, which results only from the light source  1 ′ with the larger light spot diameter  16 ′. 
         [0075]    The two light sources  1 ′ and  1 ″ or a multiple array of the two light sources  1 ′ and  1 ″ may be located in one light body, arranged next to each other or one after another with a separate or split optical system. It is also possible to use separate light bodies, which are oriented such that their axes  20 ′ intersect at the working distance  13  in order to produce a common light spot  24 ′. 
         [0076]      FIGS. 12   a  and  12   b  show a special arrangement of the combined light source  40  for an operating light  36 ′ in two cross-sectional views, which are at right angles to each other. A first light source  44  with a low color temperature and a second light source  45  with a high color temperature are arranged in this exemplary embodiment one after another on the beam axis  20  of the operating light. It is obvious that the sequence shown could be reversed as well. The light sources may be, e.g., LEDs, halogen lights, gas discharge lights or other lights known to the person skilled in the art. The light  48  and  49  of the light sources  44  and  45  is superimposed via additional reflectors  46  and  47  at the working distance  13  on a working surface  14  into a light spot  24 ″. This light spot  24 ″ comprises an area  23 ″, in which the light of both light sources is superimposed, and which has a high color temperature, and an area  22 ″, in which essentially only light from light source  44  with a lower color temperature arrives, as is also shown in  FIG. 13 . The color temperature of the light of the light sources may be set by means of transparent color filters  50  and  51  such that a desired color temperature and color distribution are obtained in the light spot  24 ″. 
         [0077]    In summary, a light spot with a radial color temperature pattern is produced, which has a relatively constant color temperature pattern in a first area and has, adjoining same, a color temperature decreasing towards the edge of the light spot, and the color temperature pattern can be selected to be such that fatigue-free working is made possible during the operation of the operating light. A physiological light perception is thus utilized during the operation by lighting an operating site with a higher color temperature in order to make high concentration and reduced fatigue possible, and a lower color temperature is provided outside the operating site in order to create a quieter picture with a lower extent of so-called overstimulation. 
         [0078]    While specific embodiments of the invention have 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. 
         [0000]    
       
         
               
               
               
             
           
               
                 APPENDIX 
               
               
                   
               
             
             
               
                   
                  1, 1′, 1″ 
                 Radiation source 
               
               
                   
                  2, 2′, 2″ 
                 LED 
               
               
                   
                  3, 3′, 3″ 
                 Optical system 
               
               
                   
                  4 
                 Printed circuit board 
               
               
                   
                  5 
                 Chip 
               
               
                   
                  6 
                 Phosphor layer 
               
               
                   
                  7 
                 Primary lens 
               
               
                   
                  8 
                 Base 
               
               
                   
                  9 
                 Contact tab 
               
               
                   
                 10 
                 Inner area 
               
               
                   
                 11 
                 Outer area 
               
               
                   
                 12, 12′, 12″ 
                 Light radiation 
               
               
                   
                 13 
                 Working distance 
               
               
                   
                 14 
                 Working surface 
               
               
                   
                 15 
                 Second diameter 
               
               
                   
                 16, 16′, 16″ 
                 First diameter 
               
               
                   
                 17 
                 Lighting intensity pattern 
               
               
                   
                 18 
                 Color temperature distribution 
               
               
                   
                 19 
                 Color rendering pattern 
               
               
                   
                 20, 20′ 
                 Light source axis 
               
               
                   
                 21, 21′ 
                 Second area 
               
               
                   
                 22, 22′ 
                 Third area 
               
               
                   
                 23, 23′ 
                 First area 
               
               
                   
                 24, 24′, 24″ 
                 Light spot 
               
               
                   
                 25, 26 
                 Refractive aspherical surfaces 
               
               
                   
                 27 
                 Reflecting TIR surface 
               
               
                   
                 28, 29 
                 Planar surfaces 
               
               
                   
                 30, 31 
                 Surfaces 
               
               
                   
                 32 
                 Refraction 
               
               
                   
                 33 
                 Reflection 
               
               
                   
                 34 
                 Surface 
               
               
                   
                 35 
                 Area for mechanical fixation 
               
               
                   
                 36, 36′ 
                 Operating light 
               
               
                   
                 37 
                 Superimposed light radiation 
               
               
                   
                 38 
                 Central LED 
               
               
                   
                 39 
                 Multiple array of LED chips 
               
               
                   
                 40 
                 Combined light source 
               
               
                   
                 41 
                 Mechanical fixing means 
               
               
                   
                 44 
                 First light source 
               
               
                   
                 45 
                 Second light source 
               
               
                   
                 46, 47 
                 Reflector 
               
               
                   
                 48, 49 
                 Light beam 
               
               
                   
                 50, 51 
                 Transparent color filter