Optical stack and manufacturing method for same, smart window including same, and automobile or windows for building using same

A method for manufacturing a variable transmittance optical stack, the method comprising:

• (a) preparing a first polarizing plate;
• (b) forming a first transparent conductive layer on a transparent substrate;
• (c) forming a second transparent conductive layer on a second polarizing plate;
• (d) forming a liquid crystal layer by coating a composition for forming a liquid crystal layer on the second transparent conductive layer;
• (e) laminating the first transparent conductive layer of the stack formed at the forming (b) to be brought into contact with the liquid crystal layer of the stack formed at the forming (d);
• and
• (f) laminating the first polarizing plate prepared at the preparing (a) on the transparent substrate of the stack formed at the laminating (e),
• wherein at the laminating (f), the first polarizing plate is laminated such that an absorption axis of the first polarizing plate and an absorption axis of the second polarizing plate are orthogonal to each other in a planar direction, and
• wherein the forming (b) to the laminating (e) are performed through a roll-to-roll process.