Snap-on lens carrier assembly for integrated chip optical sensor

Abstract

A snap-on lens carrier for optical pointing devices has retaining legs which structurally affix the lens to the IC to automatically align and register the lens with the aperture plate of the optical sensor. The lens carrier has a body portion which includes the lens and retaining legs arranged on the ends of the body portion. The retaining legs may take various forms, but in general are perpendicular to the body portion with a retaining detent formed at each of their free ends. The retaining legs are configured so that their length between a bearing area on the body portion and the detent corresponds to the thickness of an optical sensor IC. The retaining legs of the lens carrier are resiliently biased to enable the carrier to snap-on to the IC, and thus attached, the IC and lens function as an integral unit when assembled with the remaining components of the pointing device. By attaching the IC and lens in this manner the optical sensor and the lens are in fixed relation to one another and repeatedly precise registration of parts is ensured. In an optical trackball environment, the snap-on lens carrier is employed with a ball cup having an integrally molded transparent tracking window to be aligned with the lens and sensor. The ball cup supports a ball of the trackball device and prevents contamination of the optical components within the device housing.