CIRCUIT BOARD MISALIGNMENT DETECTION APPARATUS AND METHOD

• US 20020011861A1
• Filed: 05/13/1998
• Published: 01/31/2002
• Est. Priority Date: 05/13/1997
• Status: Active Grant

• Current Assignee: Nidec-Read Corporation (Nidec Corporation)
• Original Assignee: Nidec-Read Corporation (Nidec Corporation)
• Inventors: NISHIKAWA, HIDEO
• Granted Patent: US 6,353,327 B2
• Time in Patent Office: Days
• US Class Current: 324/758
• CPC Class Codes: G01R 1/06794 Devices for sensing when probes are in contact, or in position to contact, with measured object
• CPC Class Codes: G01R 31/2805 Bare printed circuit boards
• CPC Class Codes: G01R 31/2887 involving moving the probe head or the IC under test; docking stations moving single probes G01R1/06705; moving individual probes in multiple probes G01R1/07392

Abstract

Position detection electrodes are disposed so as to be point-symmetrical relative to an arbitrary point on a line X that extends almost along the center of a printed pattern on an opposite circuit board and is parallel with the Y axis. Position detector electrodes are disposed in the same manner. A probe selector switch section can provide a probe selection signal, and a position detector sensor selection which section can provide a signal for selecting among the position detection electrodes. A detected voltage varies depending on how the position detection electrode is opposed to a printed pattern. Thus, misalignment can be detected by detecting the opposition relationship between each of the position detection electrodes and the printed pattern.

Claims

1. An apparatus for detecting misalignment between an inspected circuit board and a circuit board inspection apparatus, characterized in that:

misalignment apparatus detects the variation in electrostatic capacity depending on the opposition condition between the wiring on said inspected circuit board and an electrode provided opposite to the wiring.

2. An apparatus for detecting the misalignment between an inspected circuit board and a circuit board inspection apparatus, further characterized in that the apparatus comprises:

an electrode provided opposite to the wiring on said inspected circuit board;

an electrostatic capacity detection means for detecting variation in electrostatic capacity depending on the opposition condition between said electrode and said wiring; and

a means for determining said misalignment based on the detected electrostatic capacity.

3. A circuit board misalignment detection apparatus according to claim 2 further characterized in that:

said apparatus comprises;

1) an X-direction electrode having first and second x-direction electrodes disposed to detect difference in electrostatic capacities if there is misalignment in the X direction, and

2) a Y-direction electrode having first and second Y-direction electrodes disposed to detect difference in electrostatics capacities if there is misalignment in the Y direction.

4. A circuit board misalignment detection apparatus according to claim 3 further characterized in that:

said first and second X-direction electrodes are disposed so as to be point-symmetrical relative to an arbitrary point on a line that extends almost along the center of the wiring on the opposite circuit board and is parallel with the Y axis, and in that;

said first and second Y-direction electrodes are disposed so as to be point-symmetrical relative to an arbitrary point on a line that extends almost along the center of the wiring on the opposite circuit board and is parallel with the X axis.

5. A circuit board misalignment detection apparatus according to claim 4 further characterized in that:

said first and second X-direction electrodes partly protrude from the wiring on the opposite circuit board even if there is no misalignment in the X direction and in that;

said first and second Y-direction electrodes partly protrude from the wiring on the opposite circuit board even if there is no misalignment to the Y direction.

6. A circuit board misalignment detection apparatus according to claim 3 further characterized in that:

the apparatus has two sets of X- and Y-direction electrodes, and in that;

said determination means reads the misalignment in the Θ

direction based on the electrostatic capacity detected by said two sets of electrodes.

7. A circuit board misalignment detection apparatus according to claim 4 further characterized in that:

the apparatus has two sets of X- and Y-direction electrodes, and in that;

said determination means reads the misalignment in the Θ

direction based on the electrostatic capacity detected by said two sets of electrodes.

8. A circuit board misalignment detection apparatus according to claim 5 further characterized in that:

the apparatus has two sets of X- and Y-direction electrodes, and in that;

said determination means reads the misalignment in the Θ

direction based on the electrostatic capacity detected by said two sets of electrodes.

9. A method for detecting misalignment between an inspected circuit board and a circuit board inspection apparatus, characterized in that:

misalignment is detected based on the variation in electrostatic capacity depending on the opposition condition between wiring on said inspected circuit board and an electrode provided opposite to the wiring.