Circuit board testing apparatus and method for testing a circuit board
First Claim
1. A circuit board testing apparatus for testing a plurality of wirings formed on a circuit board, each wiring having a first terminal and second terminal at opposite ends of each of the wirings, the apparatus comprising:
- an electromagnetic wave irradiator which irradiates an electromagnetic wave onto a first terminal of a selected one of the wirings to discharge electrons from the irradiated terminal by photoelectric effect;
an electrode disposed at such a position as to trap discharged electrons;
a voltage supplier operatively connected between the electrode and the second terminal of the selected wiring to apply voltage therebetween so that the electrode has a higher potential than the second terminal of the selected wiring, the voltage supplier including a probe operatively connected to the voltage supplier and connectable to the second terminal of the selected wiring;
a current detector which detects an electric current that passes through the electrode, the probe and the second terminal of the selected wiring; and
a judger which determines existence of an open-circuit in the selected wiring based on the current detected by the current detector.
1 Assignment
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Accused Products
Abstract
A circuit board testing apparatus for testing continuity and/or short-circuit of wirings formed on a circuit board, includes an electromagnetic wave irradiator which irradiates first terminals of the wirings with an electromagnetic wave so that electrons are discharged from the first terminals by photoelectric effect. Discharged electrons are trapped by an electrode which is electrically biased to have a higher potential than that of the second terminals of the wirings, thereby causing an electric current to flow through the wirings via the electrode. Existence of open-circuit and/or short-circuit of the wirings is judged based on the current flowing the wirings.
23 Citations
37 Claims
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1. A circuit board testing apparatus for testing a plurality of wirings formed on a circuit board, each wiring having a first terminal and second terminal at opposite ends of each of the wirings, the apparatus comprising:
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an electromagnetic wave irradiator which irradiates an electromagnetic wave onto a first terminal of a selected one of the wirings to discharge electrons from the irradiated terminal by photoelectric effect;
an electrode disposed at such a position as to trap discharged electrons;
a voltage supplier operatively connected between the electrode and the second terminal of the selected wiring to apply voltage therebetween so that the electrode has a higher potential than the second terminal of the selected wiring, the voltage supplier including a probe operatively connected to the voltage supplier and connectable to the second terminal of the selected wiring;
a current detector which detects an electric current that passes through the electrode, the probe and the second terminal of the selected wiring; and
a judger which determines existence of an open-circuit in the selected wiring based on the current detected by the current detector. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A circuit board testing apparatus for testing continuity and/or a short-circuit in wirings formed on a circuit board, each wiring having first and second terminals at opposite ends of the wiring, the apparatus comprising:
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an electromagnetic wave irradiator which irradiates the first terminals of the wirings with an electromagnetic wave to allow electrons to be discharged from the first terminals by photoelectric effect;
an electrode arranged to trap discharged electrons;
a voltage supplier including a probe operatively connected to the voltage supplier and connectable to at least one of the second terminals of the wirings, the voltage supplier being operatively connected between the electrode and the at least one of the second terminals to apply voltage therebetween so that the electrode has a higher potential than the at least one of the second terminals;
a current detector which detects an electric current that passes through the electrode, the probe and the at least one of the second terminals; and
a judger which determines existence of an open-circuit and/or a short-circuit in at least one of the wirings based on the current detected by the current detector. - View Dependent Claims (14)
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15. A circuit board testing apparatus for testing a plurality of wirings formed on a circuit board, each wiring having a first and second terminals at opposite ends of the wiring and the first terminals of the wirings being exposed on one surface of the circuit board, comprising:
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an electromagnetic wave irradiator which collectively irradiates the first terminals of the wirings with electromagnetic wave to discharge electrons from the first terminals by photoelectric effect;
an electrode arranged to trap discharged electrons;
a selector for selecting one of the wirings;
a voltage supplier including a probe operatively connected to the voltage supplier and connectable to at least one of the second terminals of the wirings, the voltage supplier operatively connected between the electrode and the at least one of the second terminals to apply voltage therebetween so that the electrode has a higher potential than the at least one of the second terminals;
a current detector which detects an electric current that passes through the electrode, the probe, and the at least one of the second terminals; and
a judger which judges continuity and/or a short-circuit in at least one of the wirings based on the electric current detected by the current detector. - View Dependent Claims (16, 17, 18, 19, 20)
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21. A method for testing continuity and/or a short-circuit in at least one wiring formed on a circuit board, each wiring having first and second terminals, the method comprising the steps of:
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providing an electrode operatively connected to a probe which is selectively connectable to at least one of the second terminals;
irradiating at least one of the first terminals of the wirings with an electromagnetic wave to discharge electrons from the at least one of the first terminals into a space by photoelectric effect;
trapping discharged electrons by the electrode having a potential higher than at least one of the second terminals of the wirings and allowing a current caused by trapped electrons to flow through the electrode, the probe and the at least one of the second terminals;
detecting the current that flows through the electrode, the probe and the at least one of the second terminals; and
judging continuity and/or a short-circuit in at least one of the wirings based on the current flowing through the wiring. - View Dependent Claims (22, 23, 24, 25)
enclosing the space into which electrons are discharged; and
depressurizing the space.
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23. The method according to claim 21, wherein said step of irradiating includes selectively and successively irradiating the first terminals of the wirings one by one, and an electrical potential difference is produced between the electrode and the respective second terminal of the wiring being irradiated in such a manner that the electrode has a potential higher than that of the respective second terminal.
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24. The method according to claim 21, wherein said step of irradiating includes selectively and successively irradiating the first terminals of the wirings one by one, and a difference of electric potential is produced between the electrode and a second terminal of a wiring adjacent to the wiring being irradiated in such a manner that the electrode has a potential higher than that of the second terminal of the wiring adjacent to the wiring being irradiated.
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25. The method according to claim 21, wherein said step of irradiating includes selectively and successively irradiating the first terminals of the wirings, and a difference of electric potential is produced between the electrode and the at least one of the second terminals or between the electrode and at least one of the second terminals of the wirings adjacent to the wiring being irradiated in such a manner that the electrode has a potential higher than that of the at least one of the second terminals.
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26. A circuit board testing apparatus for testing a plurality of wirings formed on a circuit board, each wiring having a first terminal and second terminal at opposite ends of each of the wirings, the apparatus comprising:
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an electromagnetic wave irradiator which irradiates an electromagnetic wave onto a first terminal of a first selected wiring to discharge electrons from the irradiated terminal by photoelectric effect;
an electrode disposed at such a position as to trap discharged electrons;
a voltage supplier operatively connected between the electrode and a second terminal of a second selected wiring to apply voltage therebetween so that the electrode has a higher potential than the second terminal of the second selected wiring, the voltage supplier including a probe operatively connected to the voltage supplier and connectable to the second terminal of the second selected wiring;
a current detector which detects an electric current that passes through the electrode, the probe and the second terminal of the second selected wiring; and
a judger which determines existence of a short-circuit in the first selected wiring based on the current detected by the current detector. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37)
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Specification