Pick and place machine with component placement inspection

• US 20070120977A1
• Filed: 01/18/2007
• Published: 05/31/2007
• Est. Priority Date: 11/13/2001
• Status: Abandoned Application

• Current Assignee: CyberOptics Corporation (Nordson Corporation)
• Original Assignee: CyberOptics Corporation (Nordson Corporation)
• Inventors: Fishbaine, David, Madsen, David, Haugen, Paul, Dale, Theodore, Duquette, David, Gaida, John, Roth, Scott, Bushman, Thomas, Liberty, Todd, Buchika, Brant
• Application Number:
  US11/654,727
• Publication Number:
  US 20070120977A1
• Time in Patent Office: Days
• US Class Current: 348/87
• 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 acquiring a plurality of images in a pick and place machine, the method comprising:

resetting photosites of a photosensitive array;

acquiring a first image on the photosites;

transferring the first image to a non-photosensitive area of the array;

resetting the photosites of the photosensitive array to clear the first image; and

generating a controlled exposure to acquire a second image before the first image is read completely from the non-photosensitive area of the array.

2. The method of claim 1, wherein transferring the first image to the non-photosensitive area includes transferring the first image to vertical registers of an interline transfer CCD array.

3. The method of claim 1, wherein transferring the first image to the non-photosensitive area includes transferring the first image to a storage area of a frame transfer CCD array.

4. The method of claim 1, wherein the first and second images are smaller than the size of an imaging area of the array.

5. The method of claim 4, and further comprising positioning the photosensitive array at an angle relative to an optical axis providing the first and second images.

6. The method of claim 1, wherein generating a controlled exposure of the second image includes obstructing all light from falling upon the photosensitive array after an integration period of the second image has elapsed.

7. The method of claim 6, wherein obstructing all light includes causing an electronically controlled optical shutter to enter a closed state thereby preventing light from passing therethrough.

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

hindering illumination not within a selected wavelength band from falling upon the photosensitive array; and

wherein generating the controlled exposure includes providing illumination within the selected wavelength band upon a placement location for a selected exposure time.

9. A method of acquiring a plurality of images of a placement location in a pick and place machine, the method comprising:

resetting photosites of a first photosensitive array;

acquiring a first image on the photosites of the first photosensitive array;

resetting photosites of a second photosensitive array; and

acquiring a second image on the photosites of the second photosensitive array;

wherein the first and second arrays acquire images sequentially through common optics.

10. The method of claim 9, wherein the first and second photosensitive arrays acquire images based on substantially monochromatic illumination.