PDT apparatus with high output LED for therapy and aiming

Information

  • Patent Application
  • 20070225777
  • Publication Number
    20070225777
  • Date Filed
    March 23, 2006
    18 years ago
  • Date Published
    September 27, 2007
    17 years ago
Abstract
An apparatus for directing light to an eye for exciting a photosensitizer includes a high output or super bright LED and an optic that receives light from the LED and concentrates the light so that it is nearly collimated. The LED is a single light source that is used for both therapy and for diagnostics or aiming.
Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING


FIG. 1 is an illustration of the optical system of the apparatus of the present invention for directing therapeutic and aiming light to a patient's eye;



FIG. 2 is a top view of an LED die having a metallization grid and at least four wirebonds in accordance with the present invention;



FIG. 3 is an illustration of the compound parabolic concentrator of the present invention;



FIG. 4 is an illustration of the position of the wirebonds on the LED die with respect to the aperture of the compound parabolic concentrator on which the die is mounted in accordance with one feature of the present invention;



FIG. 5. is an illustration of the position of the wirebonds on the LED die with respect to the aperture of the compound parabolic concentrator on which the die is mounted in accordance with another embodiment of the present invention; and



FIG. 6 is a top view of an aperture wheel in accordance with the present invention.


Claims
  • 1. An apparatus for directing light to an eye for exciting a photosensitizer comprising: a LED having a light output greater than or equal to 700 mW when driven with a current to provide therapy light having a first wavelength for exciting the photosensitizer to provide therapy;a compound parabolic concentrator having an acceptance angle that is less than or equal to 30°, the compound parabolic concentrator receiving light from the LED and directing light out with a smaller emission angle than the emission angle of the LED; andone or more optics for receiving light from the compound parabolic concentrator and directing the light out of the apparatus.
  • 2. An apparatus as recited in claim 1 wherein the LED has a 1 mm2 to 1.5 mm2 die.
  • 3. An apparatus as recited in claim 1 wherein a die of the LED has a top metallization grid with at least four wirebonds.
  • 4. An apparatus as recited in claim 3 wherein the four wirebonds are disposed near the corners of the metallization grid.
  • 5. An apparatus as recited in claim 4 wherein the metallization grid has a first metalized line in parallel with a second metalized line and a third metalized line in parallel with a fourth metalized line wherein the first and second metalized lines intersect the third and fourth metalized lines at intersection points and the wirebonds are located at the intersection points.
  • 6. An apparatus as recited in claim 1 wherein the light output of the LED is greater than or equal to 800 mW.
  • 7. An apparatus as recited in claim 1 wherein the LED can be driven by at least 2 amps of current before current roll over occurs.
  • 8. An apparatus as recited in claim 1 wherein the LED is mounted on a heat spreader.
  • 9. An apparatus as recited in claim 8 wherein the heat spreader is plated with nickel and gold.
  • 10. An apparatus as recited in claim 8 wherein the LED is secured to the heat spreader with a metal filled epoxy.
  • 11. An apparatus as recited in claim 10 wherein the metal filled epoxy is a silver filled epoxy.
  • 12. An apparatus as recited in claim 8 wherein the heat spreader is mounted on a heat sink.
  • 13. An apparatus as recited in claim 1 wherein the LED is mounted on a passive heat removal system.
  • 14. An apparatus as recited in claim 13 wherein the passive heat removal system includes a heat spreader and heat sink.
  • 15. An apparatus as recited in claim 14 wherein the passive heat removal system includes an electric fan.
  • 16. An apparatus as recited in claim 1 wherein the compound parabolic concentrator has a first surface for receiving light and a second surface through which light exits, the first surface being smaller than the second surface and wherein the LED is mounted on the first surface.
  • 17. An apparatus as recited in claim 16 wherein the LED has at least four wirebonds that are located outside of the first surface of the compound parabolic concentrator.
  • 18. An apparatus as recited in claim 16 wherein the LED is secured to the compound parabolic concentrator with an index matching silicon gel.
  • 19. An apparatus as recited in claim 1 wherein the compound parabolic concentrator has a first surface for receiving light from the LED, the first surface having a radius of 0.5 mm to 2.0 mm.
  • 20. An apparatus as recited in claim 1 further comprising a filter movable into the optical path of the LED light, the filter allowing a second wavelength of light to pass that will not excite the photosensitizer to provide therapy, the second wavelength of light providing diagnostic light or an aiming beam.
  • 21. An apparatus as recited in claim 20 wherein the therapy light has a center wavelength of approximately 664 nm and the diagnostic light or aiming beam has a center wavelength of approximately 635 nm.
  • 22. An apparatus as recited in claim 20 wherein the LED is driven by a current and is driven with less current when the LED is used to provide the diagnostic light or aiming beam than the current used to drive the LED when providing therapy light.
  • 23. An apparatus as recited in claim 20 wherein the optics for receiving light from the parabolic concentrator include a selective reflector that reflects light of the first and second wavelength towards an eye of a patient and that passes light of the second wavelength reflected from a patient's eye to optics to allow a user to see what eye tissue the aiming beam is impinging on, the selective reflector blocking light of the first wavelength that is reflected from the patient's eye.
  • 24. An apparatus as recited in claim 1 including a member having a plurality of selectable apertures of different sizes, the member being movable to position one of the apertures in the path of the LED light to control the size of the light used for therapy.
  • 25. An apparatus as recited in claim 1 wherein the member is a disk that is rotatable to position different apertures in the path of the LED light.
  • 26. A LED for use in an apparatus that directs light to an eye for therapy comprising: an LED die having a top metallization layer with a metalized grid having a first metalized line in parallel with a second metalized line and a third metalized line in parallel with a fourth metalized lines, the first and second metalized lines intersecting the third and fourth metalized lines at intersection points, and at least four wirebonds, each of the four wirebonds being located at an intersection point of the metalized lines and at a corner of the die, the LED die providing a light output greater than or equal to 700 mW.
  • 27. An apparatus as recited in claim 26 wherein the light output of the LED is greater than or equal to 800 mW.
  • 28. An apparatus as recited in claim 26 wherein the LED has a 1 mm2 to 1.5 mm2 die.
  • 29. An apparatus as recited in claim 26 wherein the LED can be driven by at least 2 amps of current before current roll over occurs.
  • 30. An apparatus as recited in claim 26 wherein the LED is mounted on a heat spreader.
  • 31. An apparatus as recited in claim 30 wherein the heat spreader is plated with nickel and gold.
  • 32. An apparatus as recited in claim 30 wherein the LED is secured to the heat spreader with a metal filled epoxy.
  • 33. An apparatus as recited in claim 32 wherein the metal filled epoxy is a silver filled epoxy.
  • 34. An apparatus as recited in claim 30 wherein the heat spreader is mounted on a heat sink.
  • 35. An apparatus for directing light to an eye for therapy comprising: at least one LED; anda compound parabolic concentrator having an acceptance angle that is less than or equal to 30° and a first surface positioned adjacent the LED for receiving light from the LED, the first surface having a radius of 0.5 mm to 2.0 mm.
  • 36. An apparatus as recited in claim 35 wherein the LED is mounted on the first surface of the compound parabolic concentrator.
  • 37. An apparatus as recited in claim 36 wherein the LED has at least four wirebonds that are located outside of the first surface of the compound parabolic concentrator.
  • 38. An apparatus as recited in claim 36 wherein the LED is secured to the compound parabolic concentrator with an index matching silicon gel.
  • 39. An apparatus as recited in claim 35 wherein the compound parabolic concentrator emits LED light that is nearly collimated.
  • 40. An apparatus for directing light to an eye for exciting a photosensitizer comprising: a LED providing light having a first center wavelength when driven by a first current to provide therapy, the LED providing light having a second center wavelength that is less than the first center wavelength when driven by a second current that is less than the first current; anda filter that is moveable into the path of the light from the LED when the LED is driven by the second current, the filter passing a waveband of light having a third center wavelength that is less than second center wavelength to provide diagnostic light or an arming beam.
  • 41. An apparatus as recited in claim 40 wherein the first center wavelength of light is approximately 664 nm to provide diagnostic light or an aiming beam.
  • 42. A method of controlling the light from a single light sensor having at least one LED to provide both therapy and light for diagnostics or an aiming beam comprising: driving the LED light source with a first current to provide therapy light having a center wavelength for therapy;driving the LED light with a second current that is less than the first current to cause a shift in the center wavelength of the LED light; andpassing the LED light through a filter when the LED is driven by the second current, the light passed by the filter having a center wavelength for diagnostics or aiming that is insufficient to provide therapy.
  • 43. A method as recited in claim 42 wherein the center wavelength of light for therapy is approximately 664 nm and the center wavelength of light for diagnostics or aiming is approximately 635 nm.
  • 44. An apparatus for directing light to an eye for exciting a photosensitizer comprising: a light source including at least one LED;a compound parabolic concentrator having a first surface adjacent to the LED light source for receiving light therefrom, the compound parabolic concentrator directing light out with a substantially smaller emission angle than the emission angle of the LED; anda member having a plurality of selectable apertures of different sizes, the member being movable to position one of the apertures in the path of the LED light output from the compound parabolics concentrator, to control the size of the light used for therapy.
  • 45. An apparatus as recited in claim 44 wherein the member is a disk that is rotatable to position different apertures in the path of the LED light.
  • 46. An apparatus for directing light to an eye for exciting a photosensitizer comprising: a light source having at least one LED, the light source having a wavelength capable of exciting the photosensitizer; anda disk having a plurality of apertures of different sizes, the disk being rotatable to position one of the apertures in the path of the LED light to control the size of the LED light used to excite the photosensitizer.