Automated domain reflectometry testing system

• US 6,759,853 B2
• Filed: 12/15/2000
• Issued: 07/06/2004
• Est. Priority Date: 12/15/1999
• Status: Expired due to Term

• Current Assignee: Brian D. Butler
• Original Assignee: Brian D. Butler
• Inventors: Butler, Brian D.
• Primary Examiner(s): Pert, Evan
• Assistant Examiner(s): PATEL, PARESH H
• Application Number:
  US09/738,044
• Publication Number:
  US 20020075009A1
• Time in Patent Office: 1,299 Days
• Field of Search: 324/124, 324/532, 324/533-535, 324/537, 324/552, 324/754, 324/642-643, 324/757, 324/761
• US Class Current: 324/534
• CPC Class Codes: G01R 1/06772 High frequency probes
• CPC Class Codes: G01R 31/11 using pulse reflection methods
• CPC Class Codes: G01R 31/2801 Testing of printed circuits, backplanes, motherboards, hybrid circuits or carriers for multichip packages [MCP] G01R31/318508 takes precedence; contactless testing G01R31/302; testing contacts or connections G01R31/66

Abstract

A robotic domain reflectometry test system (and corresponding method) comprising: domain reflectometry instrumentation; a robotic arm; and a passive, high frequency probe assembly comprising a signal probe and a ground probe having a fixed, non-adjustable pitch, the probe assembly being electrically connected to the domain reflectometry instrumentation, and being moved, electrically connected to, and retracted from test points on an electrical component to be tested by the robotic arm.

Claims

1. A robotic domain reflectometry test system comprising:

domain reflectometry instrumentation;

a robotic arm; and

a passive, high frequency probe assembly comprising a signal probe and a ground probe having a fixed, non-adjustable pitch, said probe further comprising a controlled impedance, said probe assembly being electrically connected to said domain reflectometry instrumentation, and being movable by said robotic arm in an X, Y and Z axis for placing and retracting said signal probe and said ground probe from test points on an unloaded printed wiring board (PWB), said domain reflectometry instrumentation and said probe assembly configured to measure impedance values of said test points on said PWB.

2. The system of claim 1 additionally comprising a probe assembly changing station accessible by said robotic arm, said probe assembly changing station comprising holders for a plurality of probe assemblies, each probe assembly from the plurality of probe assemblies comprising a different predetermined pitch.

3. The system of claim 2 additionally comprising a robotic control system comprising means for directing said robotic arm to acquire from said probe assembly changing station a probe assembly having a correct predetermined pitch for test points having a same pitch.

4. The system of claim 1 wherein said system can test traces having a length of between approximately 0.5 inches and 150 feet such that a standard deviation of domain reflectometry test result impedances is 0.03 ohms or less.

5. The system of claim 1 wherein said probe assembly mimics electrical characteristics of a coaxial structure.

6. The system of claim 1 wherein said system can test components comprising dimensions of between approximately 5.25 inches×

0.5 inches and 36 inches×

28.5 inches.

7. The system of claim 1 additionally comprising a robotic control system comprising means for automatically planning testing of the test points by importation of computer aided design data for the test points.

8. The system of claim 1 wherein said system records impedance and propagation delay and calculates a dielectric constant for each test point.

9. A probe assembly changing station for a robotic domain reflectometry test system, said station being accessible by a robotic arm of said system, and said station comprising holders for a plurality of passive, high frequency probe assemblies, each probe assembly comprising a different pitch between a signal probe and a ground probe and further comprising a controlled impedance, said probe assemblies affixable to a test head of the robotic arm and from which the robotic arm can affix any of the plurality of probe assemblies on the test head and locate the probe assembly in an X, Y and Z axis and automatically and accurately place said signal probe and ground probe on traces on an unloaded PWB.

10. The probe assembly changing station of claim 9 wherein each of said probe assemblies comprises a passive, high frequency probe assembly comprising a signal probe and a ground probe having a fixed, non-adjustable pitch.

11. A robotic domain reflectometry test system comprising:

domain reflectometry instrumentation;

a robotic arm;

a passive, high frequency probe assembly comprising a signal probe and a ground probe, said probe assembly being electrically connected to said domain reflectometry instrumentation said probe further comprising a controlled impedance, and being movable by said robotic arm in an X, Y and Z axis for placing and retracting said signal probe and said ground probe from test points on a trace of an unloaded PWB;

means for recording impedance and propagation delay for each test of the test points and means for calculating and recording a dielectric constant for each test of the test points.

12. A robotic domain reflectometry test method comprising the steps of:

providing to a robotic arm a passive, high frequency probe assembly comprising a signal probe and a ground probe having a fixed, non-adjustable pitch said probe assembly comprising a controlled impedance, the probe assembly being electrically connected to domain reflectometry instrumentation; and

moving the probe assembly in an X, Y and Z axis for placing and retracting the probe assembly from test points on an electrical component via the robotic arm.

13. A robotic domain reflectometry test method comprising the steps of:

providing within reach of a robotic arm a probe assembly changing station comprising holders for a plurality of passive, high frequency probe assemblies, said probe assembly comprising a controlled impedance, each probe assembly comprising a different pitch between a signal probe and a ground probe;

without human intervention affixing to a test head of the robotic arm a selected probe assembly from the plurality of probe assemblies; and

maneuvering and the selected probe assembly in an X, Y and Z axis and automatically and accurately placing the selected probe assembly'"'"'s signal probe and ground probe on test points.

14. A robotic domain reflectometry test method comprising the steps of:

providing to a robotic arm a passive, high frequency probe assembly comprising a signal probe and a ground probe, said probe assembly comprising a controlled impedance, the probe assembly being electrically connected to domain reflectometry instrumentation;

maneuvering the probe assembly via the robotic arm;

electrically connecting the probe assembly to, and retracting the probe assembly from test points on an electrical component to be tested; and

recording impedance and propagation delay for each test of the test points and calculating and recording a dielectric constant for each test of the test points.