Light source for optical sound recording and reproduction apparatus

Claim 2

A light source comprising: a green-light emitting diode having a light emitting face thereon; a sheet of fluorescent material comprising Rhodamine 6-G dye dispersed in polystyrene, supported adjacent said light emitting face, the plane of said sheet lying substantially parallel to the plane of said light emitting face; and a sheet of magnesium fluoride disposed between said sheet of fluorescent material and said light emitting face for supporting said sheet of fluorescent material, said sheet of magnesium fuoride being transparent to light emitted from said light emitting face and having an index of refraction lower than the index of refraction of said sheet of fluorescent material, whereby, light emitted from said light emitting face is absorbed by said fluorescent material and re-emitted from said fluorescent material, a portion of said re-emitted light emerging as a narrow line of light from an edge of said sheet of fluorescent material.

Claim 3

A light source for use in optical sound recording and reproduction apparatus, comprising: a sheet of fluorescent material having at least one straight edge; two sheets of transparent support material having an index of refraction less than said sheet of fluorescent material, said sheet of fluorescent material being disposed between said sheets of support material; a layer of reflective material covering the edges of said sheet of fluorescent material and the corresponding edges of said sheets of support material excepting said straight edge; a pair of light emitting diodes, each of said light emitting diodes having a light emitting face thereon, said light emitting diodes being disposed in face to face relationship, and said two sheets of support material and said sheet of fluorescent material being disposed therebetween; and a wear resistant portion comprising a strip of hard transparent material having substantially the same thickness and index of refraction as said sheet of fluorescent material and disposed in edge to edge contact with said straight edge of said fluorescent material, and two pieces of hard opaque material having substantially the same index of refraction as said support material, said strip of hard transparent material being supported between said two pieces of hard opaque material.

Claim 4

A light source for use in optical sound recording and reproduction apparatus, comprising: a sheet of fluorescent material having at least one straight edge; two sheets of transparent support material having an index of refraction less than said sheet of fluorescent material, said sheet of fluorescent material being disposed between said sheets of support material; a layer of reflective material covering the edges of said sheet of fluorescent material and the corresponding edges of said sheets of support material excepting said straight edge; a pair of light emitting diodes, each of said light emitting diodes having a light emitting face thereon, said light emitting diodes being disposed in face to face relationship, and said two sheets of support material and said sheet of fluorescent material being disposed therebetween; and a wear resistant portion comprising a strip of hard transparent material having substantially the same thickness and index of refraction as said sheet of fluorescent material and disposed in edge to edge contact with said straight edge of said fluorescent material, and two pieces of hard opaque material having substantially the same index of refraction as said support material, said strip of hard transparent material being supported between said two pieces of hard opaque material.