US 6,633,663 B1Granted

Method and system for determining component dimensional information

AssigneeInternational Business Machines Corporation

InventorKris A. Slesinger

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Abstract

A method and system for determining component dimensional information in a component placement system. The component information is derived from the pick and place equipment which is used to place the components on the substrate. The component is grasped at substantially the centroid position and moved over the aperture of a camera. The edges of the component are located, and from the edges an accurate location of the centroid may be obtained. The centroid, as well as the length, width and thickness of the component is stored in a database for use during placing of the component. Other features derived include orientation indicia obtained from component features which are viewed by the camera. During placement, all features associated with the component necessary to accurately locate the component on a substrate are obtained from the database.

Claims9

Dependent claims

A method for determining component dimensional information for placing a component on a circuit board comprising:

grasping a component at substantially the centroid of said component with a positioning tool;
positioning said component over the aperture of a camera;
detecting first and second edges of said component in the field of view of said camera;
detecting third and fourth edges of said component;
determining from said detected edges at least one dimension of said component;
storing said dimension in a component database for use in placement of said component on a circuit board,
determining a component pickup error by comparing a position of said centroid with the location of a position of a grasping tool which supports said component, and storing said component pickup error in said component database;
wherein said step for locating said second and third edges comprising:
indexing the position of said component a plurality of positions until said second and third edges are positioned in said camera aperture;
and
determining a first dimension of said component from said plurality of positions and the location of one of said edges in a field of view of said camera.

8 more elements

A system for determining component dimensional information comprising:

a component grasping tool positionable in at least first and second directions;
a camera having an aperture which is parallel to a plane defined by said first and second directions, said camera generating a plurality of pixels representing an image of a surface of said component;
a vision machine comprising a work cell controller connected to said component grasping tool for positioning said component grasping tool in said first and second directions, and connected to said camera, and an image processor and a component database, said work cell controller being programmed to execute the following steps:
incrementally positioning said component being grasped by said component grasping tool over an aperture of said camera;
processing said plurality of pixels with said image processor to locate first and second edges of said component;
indexing the position of said component grasping tool until third and fourth edges of said component are visible in said camera aperture;
based on the change of position of said grasping tool and the position of pixels which detect said third and fourth edges, determining the location of first and second diagonal corners of said component and a centroid of said component;
and
storing the location of said centroid in said component database.

6 more elements

Dependencies are inferred from the claim text.