A conductive film is applied in a wide rage of fields. Especially in fields related to displays, a conductive film is now essential for most display units such as a Plasma Display Panel (PDP), a Liquid Crystal Display (LCD) and an Organic Light Emitting Diode (OLED) display.
In application to these display related units, a gas-phase method, such as sputtering, is most commonly used, since a film formed by a gas-phase method is dense and accordingly low in resistivity as well as excellent in uniformity.
However, in a gas-phase method such as sputtering, there are problems in that large-sized equipments are required, it is not easy to maintain vacuum when forming a film having a large area, and a large quantity of energy is required to form a film. Furthermore, there are other problems such as lower formation rate, and low use efficiency of raw materials caused by low efficiency of target use.
To solve these problems, a liquid-phase method, as described below, can be used. A liquid-phase method is advantageous in that large-sized equipments are not required and energy consumption is low.
(i) A technique wherein ITO (Indium Tin Oxide) particles are dried together with a binder so as to form a film (see Patent Document 1).
(ii) A technique wherein a solution such as organic metal or mineral salt is sprayed using an atomizer onto a heated substrate and a solid phase is separated from a liquid phase so as to deposit as a film on the substrate (see Patent Document 2).
(iii) A technique wherein indium oxide and tin oxide are fixed in a sol solution which contains metal alkoxide obtained by a sol-gel method (see Patent Document 3).
(iv) A technique wherein a solution of organic metal (indium or tin) compound (complex) is coated such as to form a film, and a thin film is generated without sol-gel reaction process and fired (see Patent Document 4).    Patent Document 1: Unexamined Japanese Patent Publication No. 6-119816    Patent Document 2: Unexamined Japanese Patent Publication No. 2006-73267    Patent Document 3: Unexamined Japanese Patent Publication No. 10-237078    Patent Document 4: Unexamined Japanese Patent Publication No. 2002-42583