Liquid crystal display panel, liquid crystal display device, and polymer for alignment film material

A liquid crystal display panel that has a configuration in which a liquid crystal layer containing liquid crystal molecules is interposed between a pair of substrates, and includes a photo-alignment film on a surface of at least one substrate on a liquid crystal layer side,

• wherein in the photo-alignment film, a film formed using an alignment film material containing a polymer is subjected to an alignment treatment by photo-irradiation, the polymer including a first constituent unit exhibiting a property of controlling alignment of the liquid crystal molecules by photo-irradiation and a second constituent unit exhibiting a property of controlling alignment of the liquid crystal molecules without photo-irradiation as essential constituent units;
• the first constituent unit exhibits the property of controlling alignment of the liquid crystal molecules by at least one photo-chemical reaction selected from a photo-cross-linking reaction and a photo-isomerization reaction;
• and
• an introduction ratio of a second constituent unit exceeds 4 mol % and is equal to or less than 10 mol % on the basis of 100 mol % of a total of the first constituent unit and the second constituent unit.