Agilent Technologies, Inc.

Hewlett-Packard Company

Robert A Slutz

Tracy L Sayre

Kris J Kanack

Scott C Mason

Michael C Williams

Leanne C Pelzel

A wireless test fixture is disclosed for connecting printed circuit boards or other electrical interconnect devices having electronic components to a test system. Rigid support beams and insulating spacers are used to reduce the structural loads on the electrical interconnect plane and to minimize probe mounting plate deflections in the wireless test fixture. The test system electrical interface is via a series of floating transfer pins. The floating transfer pins provide electrical signal paths between test system interface probes and the electrical interconnect plane that interfaces with double-end sockets coupled to a probe for making electrical contact with the DUT. One or more fixed double-ended sockets and spring probes are used to make electrical contact with the DUT.

Wireless test fixture for printed circuit board test systems

A test fixture for electrically connecting a limited-access test target on a loaded circuit board with an interface probe of a tester may comprise an elongate test probe having a first end and a second end and a wireless interface printed circuit board having a first side and a second side. The first end of the elongate test probe is substantially aligned with the limited-access target on the loaded circuit board when the test fixture is positioned adjacent the loaded circuit board. A contact pad on the first side of the wireless interface printed circuit board is substantially aligned with the elongate test probe so that the contact pad contacts the second end of the elongate test probe. A contact target on the second side of the wireless interface printed circuit board is electrically connected to the contact pad on the first side of the wireless interface printed circuit board. The contact target contacts the interface probe of the tester when the test fixture is mounted on the tester.

Loaded-board, guided-probe test fixture

A test fixture for electrically connecting a plurality of limited-access test targets on a loaded circuit board with a plurality of interface probes of a tester may comprise a plurality of elongate test probes, a universal interface plate (UIP), and a wireless interface printed circuit board (WIPCB). A first end of each elongate test probe is substantially aligned with a limited-access target on the loaded circuit board when the test fixture is positioned adjacent the loaded circuit board. Each of a plurality of double-headed spring probes mounted to the UIP has a first spring loaded head located at its first end and a second spring loaded head located at its second end. Each double-headed spring probe is generally axially aligned with an elongate test probe so that its first spring loaded head contacts a second end of the corresponding elongate test probe. Each of a plurality of contact pads on the first side of the WIPCB is substantially aligned with a double-headed spring probe so that each contact pad contacts the second spring loaded head of the corresponding double-headed spring probe. Each of a plurality of contact targets on the second side of the WIPCB is electrically connected to a contact pad on the first side of the WIPCB and contacts an interface probe of the tester when the test fixture is mounted on the tester.

A test fixture for electrically connecting a limited-access test target on a loaded circuit board with an interface probe of a tester may comprise an elongate test probe having a first end and a second end and a probe-mounting plate having a first side and a second side. The first end of the elongate test probe is substantially aligned with the limited-access target on the loaded circuit board when the test fixture is positioned adjacent the loaded circuit board. A larger-pitch target on the first side of the probe-mounting plate is substantially aligned with the elongate test probe so that the larger-pitch target contacts the second end of the elongate test probe. A personality pin having a first end and a second end is mounted to the second side of the probe-mounting plate. The personality pin contacts the interface probe of the tester when the test fixture is mounted on the tester. A first end of an elongate wire is attached to the larger-pitch target. A second end of the elongate wire is attached to the first end of the personality pin. The elongate wire electrically connects the personality pin to the larger-pitch target.

A test fixture for electrically connecting a limited-access test target on a loaded-circuit board with an interface probe of a tester may comprise a solid, elongate test probe having a first end and a second end. A double-headed spring probe having a first spring loaded head located at a first end of the double-headed spring probe and a second spring loaded head located at a second end of the double-headed spring probe is generally axially aligned with the solid, elongate test probe so that the first spring loaded head contacts the second end of the solid, elongate test probe. A contact pad on a first side of a wireless interface printed circuit board is generally aligned with the second spring loaded head of the double-headed spring probe so that the contact pad contacts the second spring loaded head of the double-headed spring probe. A contact target on a second side of the wireless interface printed circuit board is electrically connected to the contact pad on the first side of the wireless interface printed circuit board and contacts the interface probe of the tester when the test fixture is mounted on the tester.

A probe plate assembly for use in a circuit board test fixture is disclosed. First and second plates are mounted substantially parallel to one another and with a space between them. Probe pins are mounted to the first plate and oriented so that they can contact a device under test on the side of the first plate opposite the space. Electrical contacts are mounted to the second plate and oriented so that they can contact a test head on the side of the second plate opposite the space. Flexible conductors electrically couple the probe pins to the electrical contacts. In a disclosed embodiment, the probe pins are spring probes, and the second plate contains clearance holes disposed adjacent the spring probes. Each of the clearance holes has sufficient diameter to allow the socket tail of one of the spring probes to pass through it without substantial friction. The result is that forces from the test head are mechanically decoupled from the first plate, thus preventing bowing of the first plate. In a further disclosed embodiment, a spacer is disposed between and near the periphery of the first and second plates. The spacer may be one continuous gasket piece forming a vacuum seal around the perimeters of the first and second plates. The spacer, as well as the first and second plates, may be made of fiberglass. The first plate may be thinner or less rigid than the second plate and may alternatively be made, for example, of transparent plexiglass.

Probe plate assembly for high-node-count circuit board test fixtures

A guided-probe test fixture is disclosed for connecting circuit cards having electronic components to a board test system. The test fixture utilizes long, leaning or vertical test probes, guide plates and limited probe tip travel in order to achieve high-accuracy, fine-pitch probing of limited-access, no-clean test targets. The guided-probe test fixture of the present invention also utilizes spring probes, probe-mounting plates, personality pins and an alignment plate in order to couple test targets with multiplexed tester resources. The guided-probe test fixture of the present invention may also utilize a universal interface plate with double-headed spring probes and/or a wireless interface printed circuit board to facilitate the electrical coupling of test targets to tester resources. Accordingly, the guided-probe test fixture of the present invention is capable of sophisticated in-circuit and functional testing of a loaded-printed circuit board containing both standard-access and limited-access, no-clean test targets. The present invention is also capable of improved probing accuracy, improved no-clean testability and improved fine-pitch probing of limited-access test targets, while at the same time capable of probing standard-access test targets.

A hybrid test fixture is described that utilizes long, leaning or vertical test probes, guide plates and limited probe tip travel in order to achieve high-accuracy, fine-pitch probing of limited-access, no-clean test targets. The hybrid test fixture of the present invention also utilizes standard spring probes and long wirewrap posts or long wirewrap wires in order to probe standard-access test targets. The hybrid test fixture of the present invention also utilizes spring probes, a probe-mounting plate, personality pins and an alignment plate in order to couple test targets with multiplexed tester resources. Accordingly, the hybrid test fixture of the present invention is capable of sophisticated in-circuit and functional testing of a loaded-printed circuit board containing both standard-access and limited-access, no-clean test targets. The present invention is also capable of improved probing accuracy, improved no-clean testability and improved fine-pitch probing of limited-access test targets, while at the same time capable of probing of standard-access test targets.

Standard-  and limited-access hybrid test fixture

Method and device are provided for use in the initial manufacture of surface mount printed circuit board assemblies or for use in the replacement and repair of J-leads surface mount electrical components on printed circuit boards.

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Loveland, CO, United States of America

Robert A Slutz