Patent ID: 7081767

Claim:
An electroconductive contact unit, comprising: a holder member having a large diameter holder hole and a small diameter holder hole; an electroconductive needle member including at least a needle portion formed at an axial end thereof protruding through the small diameter holder hole and a stem portion formed at an opposite axial end thereof received by the large diameter holder hole; and a coil spring coaxially surrounding the stem portion and including at least a first end engaged with a part of the stem portion of the needle member and a second end fixed in relation to the holder member and electrically connected to a circuit board, the coil spring resiliently urging the needle member in a direction to bring the needle portion of the needle member into contact with an object to be contacted and providing an electroconductive path between the needle member and the circuit board, wherein, at least a tip portion of the needle portion of the needle member is formed with a layer of electroconductive material resistant to oxidization or wear comprising iridium, titanium nitride, rhodium or hafnium nitride either by itself or as an alloy with gold or platinum, or a combination thereof, and at least a part of the stem portion of the needle member comprises a plated layer of highly electroconductive material.