Probe contact through small amplitude vibration for bed of nails testing
AssigneeHewlett-Packard Company
InventorsMichael L. Bullock, Ronald K. Kerschner, Stephen J. Cook
Life of this patent
Estimating the term…
Abstract
A board fixturing system employed in an automatic in-circuit tester is vibrated at a sub-ultrasonic frequency that is in substantial close proximity to a resonant frequency of at least a major portion of the fixturing system to improve the probability of establishing good electrical conductivity between the probes of the automatic in-circuit tester and predetermined contact locations on the board under test.
Claims19
In an automatic in-circuit tester with fixturing means for interfacing a printed circuit board (PCB) having electronic components mounted thereon to a plurality of test probes for applying electrical signals to and receiving electrical signals from the PCB, apparatus comprising:
- a) first means for biasing the PCB into contact with the probes at predetermined locations on the PCB;
- and,
- b) second means for vibrating the fixturing means relative to the probes at a sub-ultrasonic frequency after contact has been established between said predetermined locations and the probes;
- wherein the subultrasonic frequency is in substantial close proximity to a resonant frequency of at least a portion of the fixturing means.
In a board fixturing system for interfacing a printed circuit board (PCB) having electronic components mounted thereon to a plurality of test probes for applying electrical signals to and receiving electrical signals from the PCB, apparatus comprising:
- a) indexing means, including a motor, for biasing the PCB into contact with the probes to establish contact between the probes and predetermined locations of the PCB;
- and,
- b) control means operatively coupled to the motor for exciting the motor at a predetermined frequency for a predetermined length of time after contact has been established between the probes and said predetermined locations and thereby vibrating the indexing means relative to the probes at said predetermined frequency for said predetermined length of time;
- the probability of a poor electrical contact between said predetermined locations and the probes being decreased after said vibration;
- wherein the predetermined frequency is in substantial close proximity to a resonant frequency of at least a portion of the fixturing system.
In an automatic in-circuit tester of a type having a board fixturing system for interfacing a printed circuit board (PCB) having electronic components mounted thereon to a plurality of test probes for applying electrical signals to and receiving electrical signals from the PCB, apparatus comprising:
- a) an indexable plate carrying a plurality of push pins;
- b) a stepping motor having a shaft mechanically coupled to rotate a plurality of ball screws, there being an equal plurality of ball nuts fixed to the first plate and threadedly engaging the ball screws, rotation of the shaft in a first direction indexing the first plate relative to the PCB, the push pins urging the PCB into contact with the probes at predetermined locations;
- c) control means operatively coupled to the motor for exciting the motor at a sub-ultrasonic frequency that is in substantial close proximity to a resonant frequency of at least a portion of the fixturing system for a predetermined length of time after contact has been established between the probes and said predetermined locations and thereby oscillating the first plate and push pins relative to the probes at said sub-ultrasonic frequency for said predetermined length of time;
- the probes substantially wearing through any contamination on the PCB at said predetermined locations as a result of said oscillation, the probability of a poor electrical contact between said predetermined locations and the probes thereby being decreased after said oscillation.
Dependencies are inferred from the claim text.