Therapeutic Light Source and Method

Abstract

A therapeutic light source, for example for photodynamic therapy (PDT), comprises an air-cooled array of LED's (L x,y ), the air being vented in the vicinity of the array. The array may be mounted at the distal end of a hand piece suitable for invasive therapy. The LED's may be coupled to a light guide (W, L). The emission spectra of the LED's may be substantially limited to the range 550 to 660 nm, and preferably to one of the ranges 590 to 640 nm, 560 to 644 nm, 650 to 660 nm, and 550 to 570 nm. The therapeutic light source may comprise a non-planar array of light-emitting diodes L conforming with the shape of an external area to be treated or diagnosed. The therapeutic light source may comprise a non-planar array of independently switchable red and blue light-emitting diodes L R , L B , mounted on a flexible backing.

1 . A light source for therapy and/or diagnosis, comprising a non-planar array of discrete light-emitting diodes mounted on a head portion for attachment to the head of a patient such that light is emitted onto the face of the patient, and one or more fans for cooling the array of discrete light-emitting diodes.  
   
   
       2 . A method of treatment of the face and/or scalp, comprising illuminating respectively the face and/or scalp of a patient with light from a light source comprising a first rigid array of light-emitting diodes, a second rigid array of light emitting diodes movably connected to a first edge of the first array, and a third rigid array of light-emitting diodes movably connected to a second edge of the first array.  
   
   
       3 . A light source for therapy and/or diagnosis, comprising a support for supporting the patient and an array of light-emitting diodes mounted on a curved inner surface of a rigid cover arranged to cover at least part of the length of a patient when supported by the support.  
   
   
       4 . A light source as claimed in  claim 3 , wherein said support includes a further array of light-emitting diodes.  
   
   
       5 . A light source as claimed in  claim 4 , wherein said further array comprises a plurality of sections which are independently switchable.  
   
   
       6 . A light source as claimed in any one of  claims 3  to  5 , wherein said further array is planar.  
   
   
       7 . A light source for therapy or diagnosis, comprising an array of light emitting diodes coupled to a waveguide which tapers away from the diodes so as to concentrate light emitted by the diodes.  
   
   
       8 . A light source according to  claim 7 , including a parallel-sided light guide coupled to the waveguide so that the light emitted by the light-emitting diodes is concentrated into the parallel-sided light guide.  
   
   
       9 . A light source according to  claim 8 , wherein the parallel-sided light guide comprises one or more optical fibres and/or liquid light guides.  
   
   
       10 . A light source according to  claim 7  or  8 , wherein the waveguide is frusto-conical.  
   
   
       11 . A light source according to  claim 10 , wherein the waveguide is of acrylic or glass.  
   
   
       12 . A light source according to  claim 7  or  8 , including an array of individual heatsinks mounted on the light-emitting diodes.  
   
   
       13 . A therapeutic light source, comprising an array of light-emitting diodes arranged so that light from the light-emitting diodes is incident directly in the treatment field with an output intensity of at least 10 mW/cm 2  and a spatial intensity fluctuation of 6% or less, and means for cooling the diodes by forced air convection.  
   
   
       14 . A therapeutic light source, comprising an array of discretely mounted light-emitting diodes arranged so that light from the light-emitting diodes is incident directly in the treatment field with an output intensity of at least 10 mW/cm 2  and a spatial intensity fluctuation of 10% or less, and means for cooling the diodes by forced air convection.  
   
   
       15 . A light source as claimed in  claim 14 , wherein the light-emitting diodes are electrically connected in a parallel-series matrix.  
   
   
       16 . A light source as claimed in  claim 14 , wherein the diodes are thermally coupled to one or more heatsinks.  
   
   
       17 . A light source as claimed in  claim 14 , wherein the diodes are thermally coupled to an array of individual heatsinks.  
   
   
       18 . A light source as claimed in  claim 14 , wherein the light-emitting diodes and the heatsinks are mounted on opposite sides of a support plate.  
   
   
       19 . A light source as claimed in  claim 18 , wherein the support plate is perforated to allow air to flow around the heatsinks and light-emitting diodes.  
   
   
       20 . A therapeutic light source, comprising an array of discretely mounted light-emitting diodes thermally coupled to an array of individual heatsinks and arranged so that light from the light-emitting diodes is incident in a treatment field, and means for cooling the diodes by forced air convection.  
   
   
       21 . A light source as claimed in  claim 20 , wherein the treatment field has an extent approximately equal to that of the array of diodes.  
   
   
       22 . A light source as claimed in  claim 20 , wherein the light is incident directly in the treatment field.  
   
   
       23 . A light source as claimed in  claim 20 , wherein the spatial intensity fluctuation of the light in the treatment field is 10% or less.  
   
   
       24 . A light source as claimed in  claim 20 , wherein the spatial intensity fluctuation of the light in the treatment field is 6% or less.  
   
   
       25 . A light source as claimed in  claim 20 , wherein the light-emitting diodes and the heatsinks are mounted on a support plate.  
   
   
       26 . A light source as claimed in  claim 25 , wherein the light-emitting diodes and the heatsinks are mounted on opposite sides of the support plate.  
   
   
       27 . A light source as claimed in  claim 26 , wherein the support plate is perforated to allow air to flow around the heatsinks and light emitting diodes.  
   
   
       28 . A light source as claimed in  claim 25 , wherein the support plate is perforated to allow air to flow around the heatsinks and light-emitting diodes.  
   
   
       29 . A light source as claimed in  claim 20 , wherein light from the light-emitting diodes is not concentrated by any optical system.  
   
   
       30 . A light source as claimed in  claim 20 , wherein the light emitting diodes have emission wavelengths substantially in a range of 370 to 450 nm.  
   
   
       31 . A light source as claimed in  claim 30 , wherein the light emitting diodes have emission wavelengths substantially in a range of 400 to 430 nm.  
   
   
       32 . A light source as claimed in  claim 20 , wherein the light emitting diodes have emission wavelengths substantially in a range of 550 to 660 nm.  
   
   
       33 . A light source as claimed in  claim 32 , wherein the light emitting diodes have emission wavelengths substantially in a range of 590 to 640 nm.  
   
   
       34 . Use of a light source as claimed in  claim 20 , for cosmetic treatment of a patient.  
   
   
       35 . Use as claimed in  claim 34 , wherein the treatment comprises skin rejuvenation.  
   
   
       36 . Use as claimed in  claim 34 , wherein the treatment comprises wrinkle removal.  
   
   
       37 . Use as claimed in  claim 34 , wherein the treatment comprises biostimulation.