Patent ID: 8801913

Claim:
A method for forming thin films on flexible substrate surfaces by chemical bath deposition (CBD) in a roll-to-roll process, comprising: processing a vertically travelling continuous flexible workpiece with its surface to be deposited wetted by a number of spray nozzles but the backside remaining dry with wind knives during the whole process, and with its surface to be deposited firstly washed with clean DI water, then sprayed by a freshly mixed reaction solution, followed by a number of spray steps with a series of gradually aged reaction solutions, and finally washed, rinsed and dried; remaining the workpiece and the solutions at a constant enhanced reaction temperature by preheating all of the reactant solutions, DI water and the air before they enter a well isolated reactor, and heating the aged solution underneath the solution groove; mixing the CBD solution in seconds from two or more preheated mother liquids plus preheated DI water inside a rounded or pear shaped device with a small outlet; spraying the clean DI water, freshly mixed and gradually aged reaction solutions with a series of combinations composed of solution pipes, spray nozzles, and pumps or compressed air nozzles; spraying the freshly mixed reaction solution continuously onto the surface of a vertically travelling flexible substrate, collecting the sprayed and gradually aged solution and spraying it back onto the travelling substrate surface continuously until the predicted film thickness is obtained; washing the residue solution away from the deposited surface using minimum rinsed water to reduce volumes of the waste to be treated and the DI rinsing water.