Pick and place machine with component placement inspection

• US 20070116351A1
• Filed: 01/18/2007
• Published: 05/24/2007
• Est. Priority Date: 11/13/2001
• Status: Abandoned Application

• Current Assignee: CyberOptics Corporation (Nordson Corporation)
• Original Assignee: CyberOptics Corporation (Nordson Corporation)
• Inventors: Fishbaine, David, Roth, Scott, Madsen, David, Bushman, Thomas, Haugen, Paul, Dale, Theodore, Liberty, Todd, Duquette, David, Buchika, Brant, Gaida, John
• Application Number:
  US11/654,725
• Publication Number:
  US 20070116351A1
• Time in Patent Office: Days
• US Class Current: 382/151
• CPC Class Codes: H04N 13/194 Transmission of image signals
• CPC Class Codes: H04N 13/207 using a single 2D image sensor
• CPC Class Codes: H04N 13/218 using spatial multiplexing
• CPC Class Codes: H04N 13/239 using two 2D image sensors having a relative position equal to or related to the interocular distance H04N13/243 takes precedence
• CPC Class Codes: H04N 13/254 in combination with electromagnetic radiation sources for illuminating objects
• CPC Class Codes: H04N 2013/0081 Depth or disparity estimation from stereoscopic image signals
• CPC Class Codes: H05K 13/0812 the monitoring devices being integrated in the mounting machine, e.g. for monitoring components, leads, component placement
• CPC Class Codes: H05K 13/0818 Setup of monitoring devices prior to starting mounting operations; Teaching of monitoring devices for specific products; Compensation of drifts during operation, e.g. due to temperature shifts
• CPC Class Codes: Y10T 29/49778 with aligning, guiding, or instruction
• CPC Class Codes: Y10T 29/53087 with signal, scale, illuminator, or optical viewer
• CPC Class Codes: Y10T 29/53191 Means to apply vacuum directly to position or hold work part

Abstract

Improved component placement inspection and verification is performed by a pick and place machine. Improvements include stereovision imaging of the intended placement location; enhanced illumination to facilitate the provision of relatively high-power illumination in the restricted space near the placement nozzle(s); optics to allow image acquisition device to view the placement location from an angle relative to a plane of the placement location, thereby reducing the possibility of such images being obstructed by the component; techniques for rapidly acquiring images with commercially available CCD arrays such that acquisition of before and after images does not substantially impact system throughput; and image processing techniques to provide component inspection and verification information.

Claims

1. A method of calibrating an off-axis image system in a pick and place machine, the method comprising:

placing a known target in an intended placement location;

acquiring an off-axis image of the known target;

determining initial positions of known artifacts on the known target from the acquired image; and

calculating a transformation matrix.

2. The method of claim 1, and further comprising:

after the step of acquiring an off-axis image, presenting the known target at a different position along a z-axis;

acquiring at least one additional image of the known target at the different position; and

determining adjusted positions of known artifacts on the known target from the at least one additional image; and

comparing the initial positions to the adjusted positions to refine the transformation matrix.

3. A method of calibrating a plurality of image acquisition devices in a pick and place machine, the method comprising:

placing a known target in an intended placement location;

acquiring an image of the known target with each image acquisition device;

determining positions of known artifacts on the known target from the acquired images; and

comparing the determined positions from each acquired image to calibrate for depth.