Probe assembly including touchdown sensor

Abstract

A probe assembly for use at a test station for contacting a target on an electrical circuitry component. The probe assembly includes an elongate tubular housing with a base of insulative material rigidly supported in the housing adjacent one end thereof. An interior beam assembly connects a contact block to the base with this beam assembly including a relatively flexible cantilever beam. A relatively rigid second beam assembly extends from the contact block beyond the other end of the housing and holds a probe point for contacting the target. The probe assembly also includes an upper contact held by the housing and extending into the housing cavity toward the contact block, and a lower contact held by the housing and extending into the cavity toward the contact block. The spacing between the upper and lower contacts is greater than the height of the contact block and the surfaces of the contact block facing the contacts are conductive. The contact block engages the lower contact when the probe does not engage the target, the block moves out of engagement with the lower contact after the probe point engages the target, and the block moves into contact with the upper contact when the force applied by the point against the target reaches a predetermined magnitude.