Diomed Inc.

Scientific Generics Limited

Anthony Raven

John Marshall

Robin Michael Lee

Laser diode drive circuit

An optical system for producing a high power light source comprises a number of laser diodes, or similar sources, which emit light from an emission stripe 8 having a long dimension a (x-axis) and a short dimension b (y-axis) and which have a higher numerical aperture in the y-axis than in the x-axis. The laser beams 9 are collimated by a lens 10 and focused onto an optical fiber by a further lens 20. Prior to the focusing, the collimating beams 11 are anamorphically expanded/reduced by beam shaping means 12 so that the width of each beam 11 in the x-axis is increased in relation to the width in the y-axis. The images 21 produced on the fiber end are thus anamorphically magnified so that thte anamorphic ratio between the magnification of the stripe 8 in the y-axis and in the x-axis is greater than one. By the brightness theorem, this anamorphic magnification results in a correspondingly relative decrease in the y-axis numerical aperture to enable a corresponding increase in the number of beams 11, which can fit into the solid angle of the target.

High power light source

Solid state laser diode light source

The invention provides a photocoagulator using an infrared laser diode source (70). A dichroic beam splitter (68) is used to combine the optical path of the laser system with the viewing system. Such an arrangement affords the clinician an uninterupted, uncolor view of the patient's eye during treatment, without any risk of damage to the clinician's eye. There is also provided an alignment system using a visible laser diode (80). The alignment system may include a number of mutually non parallel beams which pass through different portions of the pupil and provide information on aim, focus and vignetting.

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Royston, United Kingdom

Anthony Raven