Light-emitting devices and lens therefor

A lens for conditioning the optical output of a light-emitting source having an optical output axis and a characteristic viewing angle for coupling onto a light guide, wherein said lens comprises

• a beam diverging portion, and a beam converging portion,
• said beam diverging portion having an optical axis which is parallel or substantially co-axial with the optical output axis of said light-emitting source;
• and said beam diverging portion being adapted to diverge light coming from said light-emitting source along a first optical plane about the optical axis, said optical axis lying within said first optical plane,
• wherein said beam converging portion is adjacent said beam diverging portion, and said beam converging portion is arranged so as to converge light coming from said light-emitting source away from said light-emitting source;
• and
• wherein another beam converging portion for converging light coming from said light emitting source away from a light emitting source is adjacent said beam diverging portion such that said beam diverging portion of said lens is intermediate said beam converging portion and said another beam converging portion;
• and
• both said beam diverging portion and said beam converging portion and said another beam converging portion are intermediate a pair of beam collimating lens portions, and
• said pair of beam collimating lens portions being along a plane orthogonal to said first plane and being substantially parabolic such that the optical output from the light-emitting source along said orthogonal plane is collimated towards said light guide in a direction towards said optical output axis.