Compound lens for use with illumination sources in optical systems

An optical emitter comprising:

• a light emitting diode;
• and
• a compound lens positioned over the light emitting diode, the compound lens including:
• a first lens element having a light receiving surface and a light emitting surface,
• a second lens element having a light receiving surface and a light emitting surface, wherein the first and second lens elements are integrally joined to each other along an interface between the light emitting surface of the first lens element and the light receiving surface of the second lens element, wherein the first and second lens elements are co-molded from a silicone resin, wherein the first lens element is in optical alignment along a common optical axis with the second lens element, and wherein the first and second lens elements are optically coupled to each other to reduce the optical path difference of light propagating through the compound lens,
• a third lens element having a light receiving surface and a light emitting surface, wherein the third lens element is a bi-concave frusto-conical lens and is integrally joined to the second lens element along an interface between the light emitting surface of the second lens element and the light receiving surface of the third lens element, and
• a fourth lens element having a light receiving surface and a light emitting surface, wherein the fourth element is a bi-convex aspheric lens and wherein the third and fourth lens elements are integrally joined to each other along an interface between the light emitting surface of the third lens element and the light receiving surface of the fourth lens element.

A method of manufacturing an optical emitter comprising:

• providing a silicone resin molding compound;
• providing a mold including an upper mold member and a lower mold member defining a compound lens mold cavity;
• injecting the silicone resin molding compound to within the compound lens mold cavity;
• curing the resin molding compound to form a compound lens, the compound lens including a plurality of lens elements having a light receiving surface and a light emitting surface;
• over-molding a lens holding member onto the compound lens;
• removing the compound lens from the mold;
• and
• positioning the compound lens over a light emitting diode, thereby giving the optical emitter, wherein the plurality of lens elements are integrally joined to each other sequentially along an interface between the light emitting surface of one lens element and the light receiving surface of an immediately adjacent lens element.