Patent ID: 7639862
Filing Date: 2009-12-29
Classification: G01N,G06T

Abstract:
1. An automated computer-controlled method for measuring the quality of a pigment dispersion, the pigment dispersion being prepared by: i) combining a suitable resin with the pigment to be measured to form a paint or paste; and ii) depositing a quantity of the paint or paste at a deep end of a tapered path of a Hegman gage block in sufficient quantity to substantially fill the tapered path, the method comprising: a) placing the Hegman gage block in a holder in a motorized drawdown device, the holder sensing the presence of the gage block and signaling the computer that the gage block is present; b) activating the motorized drawdown device to lower a scraper onto the Hegman gage block and drawing the scraper along the length of the tapered path at an angle to the plane of the block and at a contact pressure sufficient to form a tapered film sample whose thickness tapers from a maximum thickness of over one hundred microns to a minimum thickness of zero; c) waiting a time interval; d) arranging a light source, a first spherical mirror, the sample, a second spherical mirror, a lens, and a camera having a two-dimensional photodetector array, in a bright field arrangement, so that the light source and the first spherical mirror are capable of illuminating the sample in a substantially collimated manner at a light intensity level sufficient to reflect light rays from the sample to the second spherical mirror whereby the second spherical mirror is capable of directing the light rays to the lens of the camera; e) acquiring an image of the sample with the two-dimensional photodetector array of the camera; f) digitizing and storing the image in a memory in the computer; and g) analyzing the image within a region of interest corresponding to the tapered film sample along the tapered path to detect and count agglomerates in the pigment that protrude above the surface of the sample.