Measurement system
AssigneeMV Research Limited
InventorsPeter Conlon, Sean Michael O'Neill, James Mahon
Life of this patent
Estimating the term…
Abstract
A measurement system (1) has robotic system (3) mounted over a base plate (2) which provides a vertical height reference. In the optical head (8), a CCD camera (17) is adjustable to be pre-set in height. The optical head (8) also has an upper light source (18) comprising LEDs and a lower light source (25) comprising a white fluorescent lamp (26) for lateral component illumination. An air flow system (45) directs cooling air in a swirling motion around the tube. An image analysis computer (10) automatically performs various tests to co-ordinate optical and mechanical operation.
Claims17
A measurement system comprising:
- a robotic system mounted on a base;
- an optical head driven by said robotic system and having a light source means and a camera;
- an image analysis computer connected to the optical head and having means for capturing circuit board images and, said image analysis computer using the images to measure component locations;
- said camera being mounted on said optical head in a vertically adjustable manner;
- said light source means including an upper set of light emitting diodes mounted in a ring arrangement for near-on-axis illumination, and means for switching said light emitting diodes;
- a lower annular light source;
- said image analysis computer including
- a frame grabber with a jitter value of less than 5 ns;
- means for performing automated repeatability tests, said means for performing, for each of a plurality of optical head acceleration values, a plurality of component measurements including recording time duration and a standard deviation of the measured component location;
- means for plotting responses of said standard deviation and time versus acceleration;
- means for determining an optimum optical head acceleration value based on both of said plotting responses analyzed in conjunction with each other;
- means for performing automatic scaling by directing movement of a reference target to an optical field of view;
- means for directing robotic movement of a target within accuracy of less then +/-5.0 microns over a working area;
- means for determining a corresponding movement in an image as a number of pixels;
- means for determining a correlating relationship between the robotic and image movements;
- means for using said correlating relationship to determine and store a fresh scaling factor;
- means for, in real time, recognizing a component larger than the field of view by its measured location and by reference to a database indicating such components by a data record flag;
- means for directing capture of an image for each of a plurality of rows of pads;
- means for storing an offset for each image in a database;
- means for performing measurements for each row of pads in isolation;
- means for retrieving the stored offsets;
- means for combining the measurements to yield a measurement for the whole component;
- and
- means for directing a second pass for components which are identified in a database as potentially having different identification colors, the second pass being initiated according to comparisons with grey scale thresholds on the first pass and being limited to a pre-defined area of the component.
Dependencies are inferred from the claim text.