Importance

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Abstract

A method and apparatus for premetered 'patch' coating discrete, incremental surfaces or substrates, such as printed circuit boards, integrated circuits and the like, with a pre-configured layer of a liquid in which a controlled volume per unit area of the liquid is applied to the substrate are disclosed. The liquid is dispensed from an applicator slot that is fluidly coupled to a liquid containing chamber. The volume of the liquid in the liquid containing chamber is varied in order to (1) sharply and distinctly start the coating 'patch' by producing a pulse of liquid that flows out of the applicator slot to form a connecting bead of liquid coating on the coating surface and (2) sharply and distinctly terminate the coating 'patch' by removing the bead of liquid connecting the applicator slot with the coated surface. The width of the coated 'patch' is determined by the length of the applicator slot. Relative movement is provided between the applicator slot and the coating surface at least during the period between formation and termination of the bead of liquid in order to produce the desired 'patch' length of liquid coating having predefined boundaries and a predetermined, uniform coating thickness.

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First Claim