Liquid crystal display device and method for producing same

A liquid crystal display device comprising:

• a pair of substrates;
• a liquid crystal layer between the pair of substrates, the liquid crystal layer containing liquid crystal molecules;
• an alignment film between the liquid crystal layer and at least one of the pair of substrates, the alignment film containing a polyamic acid or a polyimide with an imidization ratio in the range of 20 to 80%, which results in reduced residual DC voltage;
• and
• a monomolecular film between the liquid crystal layer and the alignment film,
• wherein the polyamic acid or the polyimide of the alignment film includes a photoreactive functional group,
• wherein the monomolecular film includes a structure that is derived from a silane-based surfactant that contains the following chemical formula (1) or (3):
• Cl3Si—(CR12)n—CR23 (1),
• or
• Cl3Si—(CR12)n—NH2 (3),
• wherein each R1 is the same as or different from each other, wherein each R1 represents a hydrogen atom or a halogen atom,
• wherein each R2 is the same as or different from each other, wherein each R2 represents a hydrogen atom or a halogen atom, and wherein n represents an integer of 3 to 17,
• wherein the monomolecular film is a single layer formed of a same material that covers and is in contact with the entire surface of the alignment film so that the silane-based surfactant included in the monomolecular film reacts with carboxyl groups in the alignment film to form a covalent bond that is between a structure derived from a carboxyl group in the alignment film and silicon in a structure derived from the silane-based surfactant, and is represented by the following chemical formula (2):
• wherein a pretilt angle of the liquid crystal molecules satisfies at least one of 0°<θ≦8° and 81°<θ≦90° due to the alignment film having undergone a photo-alignment treatment after forming the monomolecular film, which results in minimal changes in aligning ability of the alignment film,
• wherein the silane-based surfactant included in the monomolecular film is configured to be adsorbed on carboxyl groups in the alignment film to thus lower the concentration of residual carboxyl groups contained in the alignment film, which results in improved voltage holding ratio (VHR), and
• wherein the residual DC voltage is less than or equal to 150 mV, and the VHR is more than or equal to 98.0%.