Patent ID: 8807032
Filing Date: 2014-08-19
Classification: B41F,B41P

Abstract:
1. A method of controlling register errors with ultra-precision in a system of a continuous roll-to-roll printing process for manufacturing electronic devices, the system having N printing cylinders having numerical orders of 1, 2, . . . , i, . . . N, respectively, where N is an integer equal to or greater than 3, and a material continuously fed to the printing cylinders for printing the electronic devices thereon, the method comprising the steps of: (a) measuring a first register error for the material, after the material having passed through a second printing cylinder; (b) calculating a first feedback speed variation of the second printing cylinder to compensate for the first register error; (c) changing the speed of the second printing cylinder by the first feedback speed variation of the second printing cylinder; (d) measuring a second register error for the material, after the material having passed through a third printing cylinder; (e) calculating a second feedback speed variation of the third printing cylinder to compensate for the second register error; (f) calculating a first feedforward speed variation of the third printing cylinder by using as an input the first feedback speed variation of the second printing cylinder; and (g) changing the speed of the third printing cylinder by a net speed variation of the third printing cylinder equal to the addition of the second feedback speed variation of the third printing cylinder and the first feedforward speed variation of the third printing cylinder, wherein in step (f) the first feedforward speed variation of the third printing cylinder, V where V 2 is the first feedback speed variation of the second printing cylinder, τ is a time constant, and s is a Laplace domain variable (complex variable), and wherein τ is calculated by an equation of L/V, L designating a length of a span between adjacent cylinders and V and ν designating an operating speed of the system of a continuous roll-to-roll printing process in Laplace domain and in time domain, respectively.