Abstract:
Phototherapy devices for phototherapy treatment of a patient include a light emitter for emitting light received from a light source. Means may be provided for increasing the amount of power to the light source in response to a decrease in light output to maintain a substantially constant light output. The light source may be inside a housing and bonded to a heat sink attached to the back side of the housing to dissipate excess heat generated by the light source. Also the light source may comprise at least one LED that generates blue light output bands and at least one other LED that generates other color light output bands that are selectively mixed with the blue light output bands.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. patent application Ser. No. 11/851,616, filed Sep. 7, 2007, which is a division of U.S. patent application Ser. No. 10/919,884, filed Aug. 17, 2004, now U.S. Pat. No. 7,305,163, dated Dec. 4, 2007. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention relates to phototherapy devices including fiber optic light emitters that receive light from one or more light emitting diodes (LEDs). 
       BACKGROUND OF THE INVENTION 
       [0003]    Phototherapy has long been used to treat various known conditions including, for example, jaundice in newborn infants. Jaundice is caused by a build up of bilirubin in the blood of infants. Exposing the infant&#39;s skin to certain types of light will quickly reduce the bilirubin to a safe level. Such treatment is generally only needed for a few days, until the infant&#39;s liver is mature enough to process the bilirubin. 
         [0004]    One type of phototherapy device that is commonly used in phototherapy treatment comprises a fiber optic light emitter having fiber optic end portions that receive light from a halogen lamp or other relatively high wattage light source to obtain the desired amount of light output from the light emitter. The problem with using relatively high wattage lamps as the light source is that they are not very efficient and produce large amounts of heat that require the use of a fan to cool the light source. Incorporating a fan into the light source makes the light source quite noisy during operation and substantially increases the overall cost and size of the light source. Also such relatively high wattage lamps typically have a relatively short life and provide less light over time. 
         [0005]    A need thus exists for a fiber optic phototherapy device that may be lighted by a light source that requires considerably less wattage to operate while still producing substantially the same amount of light output from the fiber optic light emitter for a given unit surface area. 
         [0006]    A need also exists to be able to selectively light different segments or areas of a fiber optic light emitter at the same or different times as desired to allow the light to be turned off to different segments or areas if not needed. This not only saves on power, but may also reduce the amount of light to which care providers are exposed. Some care providers are very sensitive to certain bands of light, particularly blue bands which are especially effective for phototherapy treatment. By cutting down on the amount of light from the light emitter to which the care provider may be exposed, there will be less stress on the care provider caused by light exposure. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention relates to phototherapy devices including fiber optic light emitters having optical fiber end portions at one or both ends that receive light from one or more light emitting diodes (LEDs) for transmission of the light to the light emitters for emission therefrom. 
         [0008]    In accordance with one aspect of the invention, the light from one or more LEDs is focused on the optical fiber end portions at one or both ends of the light emitters for transmission of the light to the light emitters. 
         [0009]    In accordance with another aspect of the invention, one or more lenses may be used to focus the light from the LEDs on the optical fiber end portions. 
         [0010]    In accordance with another aspect of the invention, the LEDs may be mounted on a heat sink to dissipate any excess heat generated by the LEDs. 
         [0011]    In accordance with another aspect of the invention, the optical fiber end portions may be randomly mixed together and separated into a plurality of groups of end portions that receive light from a plurality of LEDs to provide a more uniform light output distribution from the light emitters. 
         [0012]    In accordance with another aspect of the invention, the optical fiber end portions of different segments or areas of fiber optic light emitters may be grouped together in different groups and lighted by different light sources that may be selectively lighted for selectively lighting one or more of the segments or areas of the light emitters at the same or different times as desired. 
         [0013]    In accordance with another aspect of the invention, LEDs having different bands of light may be focused on the same or different groups of optical fiber end portions of fiber optic light emitters. 
         [0014]    In accordance with another aspect of the invention, the fiber optic light emitters may have optical fiber end portions extending from both ends of the light emitters that are mixed together for lighting both ends using one or more light sources. 
         [0015]    In accordance with another aspect of the invention, the amount of power applied to the LEDs may be increased in accordance with a preprogrammed power curve based on an average life curve of the LEDs as the LEDs age over time or in response to a decrease in the light output from the LEDs to maintain a substantially constant light output from the LEDs over time. 
         [0016]    These and other objects, advantages, features and aspects of the present invention will become apparent as the following description proceeds. 
         [0017]    To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter more fully described and particularly pointed out in the claims, the following description and the annexed drawings setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but several of the various ways in which the principles of the invention may be employed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0018]    In the annexed drawings: 
           [0019]      FIG. 1  is a schematic top plan view, partly in section, of one form of fiber optic phototherapy device of the present invention; 
           [0020]      FIGS. 2-5 ,  7  and  8  are schematic top plan views, partly in section, of other forms of fiber optic phototherapy devices of the present invention; and 
           [0021]      FIG. 6  is a schematic fragmentary longitudinal section showing one form of fiber optic light emitter of the fiber optic phototherapy devices of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0022]    Referring now in detail to the drawings, and initially to  FIG. 1 , there is shown one form of phototherapy device  1  in accordance with this invention for use during phototherapy treatment of a patient including a fiber optic light emitting member  2  having one or more layers  3  of individual optical fibers  4  arranged in close proximity to each other. Each optical fiber includes a light transmitting core portion of a suitably optically transparent material and an outer sheath of a second optically transparent material having a different index of refraction than the core material to prevent the escape of light along its length. The core material may either be made of glass or plastic or a multi-strand filament having the desired optical characteristics. The outer sheath material is also optically transparent, but because its index of refraction is different than that of the core material, substantially total internal reflection is obtained at the sheath-core interface, as well known in the art. 
         [0023]    Optical fibers  4  may extend beyond one or both ends of light emitter  2  where they may be bundled into one or more groups of optical fiber end portions  5  to form one or more light cables  6  for transmitting light from a remote light source  7  to the light emitter as described hereafter. In  FIG. 1  the optical fibers are shown extending outwardly beyond one end only of the light emitter and bundled together to form a single light cable  6 . At the outermost end of the light cable  6  is a connector assembly  8  which may consist of a suitable buffer material  9  surrounding the gathered optical fiber end portions and a ferrule  10  crimped onto the buffer material which squeezes the buffer material and packs the optical fiber end portions substantially solid. 
         [0024]    Light emitter  2  is generally in the shape of a relatively thin light panel  11  having a greater width than thickness and opposite ends and sides and top and bottom surfaces, giving the light emitter increased flexibility. The light emitting surface  12  of the light panel  11  is typically larger than the cross-sectional area of the light cable to reduce energy density by spreading the light over a larger surface area at the light emitting surface. 
         [0025]    A protective cover  15  made of a suitable flexible translucent or transparent material may surround the light emitter. Also a protective sleeve  16  made of a suitable flexible opaque or reflective material may surround light cable  6  for easy maneuverability to facilitate connection of the connector assembly  8  or other suitable attachment device at the outer end of the light cable to a remote light source  7  for transmission of the light through the light cable to the light emitter in a manner well known in the art. Suitable filters (not shown) may also be interposed between the light receiving end of the light cable and light source  7  to filter out any undesired frequencies of light, for example, infrared or ultraviolet, allowing only those light frequencies desired to pass through the light cable. 
         [0026]    To cause light that is transmitted to light emitter  2  by light cable  6  to be emitted from the light emitter, the cladding on the outer surface of the optical fibers may be disrupted as by marring, abrading, scratching or otherwise causing mechanical, chemical or other disruptions at one or more areas along the length and width of the light emitter. The amount of light emitted at these locations is a function of the depth, size and/or frequency of such disruptions. For example, if the disruptions on the outer surface of the optical fibers are made larger and/or deeper and/or closer together as the distance from the light receiving end of the light emitter increases, there will be more uniform emission of light from the light emitter. 
         [0027]    A suitable back reflector (shown at  17  in  FIG. 6 ), made for example of Mylar or other suitable light reflective material, may be adhered to the back side of the light emitter for reflecting any light directed toward the back side back out the front side to provide illumination during phototherapy treatment. 
         [0028]    Light source  7  may comprise one or more light emitting diodes (LEDs)  18  (including organic light emitting diodes (OLEDS) and poly light emitting diodes (PLEDs)) suitably mounted inside a housing  19 . Light from the LEDs is focused on the outermost ends of light cables  6  whose connectors  8  extend into the housing through one or more openings  20  in the housing.  FIG. 1  shows one such LED  18  mounted inside housing  19  with its light focused on the outermost end portion of one light cable  6  extending into the housing through opening  20  in alignment with the LED, whereas  FIG. 2  shows two such LEDs  18  for end lighting two light cables  6  extending into the housing. 
         [0029]    The actual number of LEDs  18  within a given light source  7  may vary depending on the particular wattage output of the LEDs and the desired amount of light output to be emitted from the light emitter  2  per unit light emitting surface area  12 . A quarter inch diameter connector type ferrule  10 , which is typically used to bundle together 400 optical fiber end portions, is optimum for focusing light from an LED light source onto such bundled optical fiber end portions. If one watt LEDs are used as the light source, it has been found that twelve such LEDs can provide a unit area light output from a light emitter comprised of 4800 optical fibers that is equivalent to that produced using a 120 watt halogen lamp light source. Twelve such LEDs can optimally light 4800 optical fibers, e.g., 400 optical fiber end portions crimped together in each of twelve ferrule type connectors. Of course, if higher wattage LEDs are used as the light source, for example three watt LEDs instead of one watt LEDs, the number of LEDs needed to produce the same unit area light output would be considerably less. 
         [0030]    From this it is apparent that it is much more efficient to use small LEDs as the light source instead of a single high wattage light source such as a halogen lamp. Also LEDs are much longer lasting than high wattage light sources, and have a more useful blue light band width for phototherapy treatment than high voltage light sources. Further, LED light sources do not require a fan to cool the light sources as do high wattage light sources, thus eliminating the noisiness of a fan during use and allowing the light source to be made much smaller than light sources using high wattage light sources. At most all that may be needed to dissipate any excess heat generated by the LEDs would be to mount the LEDs to a heat sink  21  which may be attached to the back side of the housing and may have fins  22  protruding therefrom to further dissipate the heat as schematically shown in the majority of the drawing figures. 
         [0031]    Higher wattage LEDs, up to five watts each, are also available for use as a light source. However, these higher wattage LEDs have a wider light dispersion angle, making them more difficult to focus the light on the outermost ends of the optical fiber light cables. 
         [0032]    The optical fiber end portions  5  at one or both ends of a fiber optic light emitter  2  may be separated into more than one group  23  of end portions with the end portions of each group tightly secured together by ferrule type connectors  8  tightly surrounding the end portions of the respective groups for receiving light from one or more LEDs  18  as schematically shown in  FIG. 2 . Also the optical fiber end portions of a given light emitter  2  may be randomly mixed together prior to being separated into a plurality of groups  23  of optical fiber end portions as schematically shown in  FIG. 4  to provide a more uniform light output distribution from the light emitter. 
         [0033]    Further, the optical fiber end portions of different segments  24  of a light emitter  2  may each be grouped together in different groups  23  and the groups of optical fiber end portions for the different segments lighted by different LEDs  18  as schematically shown in  FIG. 5  for selectively lighting any or all of the segments  24  of the light emitter at the same or different times as desired. 
         [0034]    The advantage in being able to selectively light different segments or areas  24  of a fiber optic light emitter  2  is that it allows different segments of the light emitter to be turned off if not needed or if light is being wasted because of the relatively small surface area of a patient being subjected to phototherapy. Not only does this save on power, it also reduces the amount of light to which care providers may be exposed. Some individuals are very sensitive to certain bands of light, particularly blue bands which are especially effective for phototherapy. By cutting down on the amount of light from the light emitter than can be seen by the care provider, for example, when an infant receiving phototherapy treatment is placed on a relatively large/wide light emitter, there will be less stress on the care provider due to light exposure. Also the light output from LEDs  18  having different bands of light may be mixed with LEDs  18  having blue light bands in an attempt to reduce its effect on making same people nauseous. 
         [0035]    Suitable lenses may also be used to focus the light from one or more LEDs onto the outermost ends of the optical fiber light cables.  FIGS. 1 and 2  schematically show lenses  25  for focusing light from a single light source onto one or more groups  23  of optical fiber end portions of a single light cable  6 . Also, a multi-faceted lens  26  may be used to focus light from two or more LEDs  18  onto the optical fiber end portions of a single light cable  6  as schematically shown in  FIG. 3 . 
         [0036]    To increase the unit area light output from a given fiber optic light emitter, the light emitter may include plural layers  3  of optical fibers  4  as schematically shown in  FIG. 6 . Also the optical fibers  4  in each layer may have end portions  5  that are mixed together and grouped with the end portions of other layers as further schematically shown in  FIG. 6  for producing a more uniform light output distribution from the light emitter. Further, the light emitters  2  may have fiber optic end portions extending from both ends of the light emitters that may be separated into a plurality of groups  23  of end portions and tightly secured together by ferrule type connectors  8  surrounding the fiber optic end portions of the respective groups for lighting by different LEDs  18  at both ends of the light emitter as schematically shown in  FIG. 7 . Alternatively, the optical fiber end portions at one end of the light emitter may be looped back and mixed with the optical fiber end portions at the other end of the light emitter for lighting both ends of the light emitter using the same LEDs  18  as schematically shown in  FIG. 8 . 
         [0037]    Over time the light output of the LEDs diminishes. To provide a more constant light output from a light emitter  2  over a longer period of time using LEDs as the light source, a feedback loop  30 , schematically shown in  FIG. 2 , may be employed that includes a photocell  31  that detects the light output from the LEDs, and a circuit  32  that increases the power to the LEDs with decreased light output to maintain a substantially constant light output. The photocell  31  may be set up to detect stray light from the LEDs as schematically shown in  FIG. 2  which is proportional to the light output from the LEDs. Alternatively, a preprogrammed power curve based on an average light curve of the LEDs may be used to increase the power to the LEDs as the LEDs age over time. 
         [0038]    Although the invention has been shown and described with respect to certain embodiments, it is obvious that equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of the specification. In particular, with regard to the various functions performed by the above-described components, the terms (including any reference to a “means”) used to describe such components are intended to correspond, unless otherwise indicated, to any component which performs the specified function of the described component (e.g., that is functionally equivalent) even though not structurally equivalent to the disclosed component which performs the functions in the herein exemplary embodiments of the invention. In addition, while a particular feature of the invention may have been disclosed with respect to only one embodiment, such feature may be combined with one or more other features of other embodiments as may be desired or advantageous for any given or particular application.