Lens cap for transistor outline package

The present invention generally relates to lens caps for transistor outline packages adapted to package optoelectronic components, and particularly to ball lens caps for said transistor outline packages. A lens cap () for a transistor outline package includes a lens part () and a hollow main part () adapted for receiving optoelectronic components. The lens part includes a ball lens () having a first groove () and a sprue filling portion () having a second groove (). The main part defines an opening () which comprises a ball lens receiving hole () and a sprue (). A protruding sidestep () is formed along an inner surface of the sprue. The lens part is firmly coupled to the main part through engagement of the protruding sidestep with the second groove and a circular rim () of the main part with the first groove. The lens cap is manufactured by insert molding the lens part in the opening, with an injection hole () feeding into the sprue. Thus, gluing is avoided, and the ball lens optics are consistently good.