Display device and manufacturing method thereof

A manufacturing method of a display device comprising:

• a first substrate including:
• a plurality of pixel electrodes provided in a plurality of pixels constituting a display area;
• an insulating layer formed in a grating shape defining openings in each of the pixels;
• and
• a first alignment film above the pixel electrodes and the insulating layer;
• a second substrate including a common electrode and a second alignment film facing the first alignment film;
• and
• a liquid crystal layer provided between the first alignment film and the second alignment film and containing a streaky polymer and a plurality of liquid crystal molecules, wherein
• the first alignment film comprises:
• a protrusion generated by the insulating layer;
• and
• a plurality of flat areas formed in the pixels, surrounded by the protrusion and overlapping the openings, respectively, and parallel to a horizontal plane of the first substrate, and
• a first director of each of the liquid crystal molecules located near the flat areas is parallel to the horizontal plane in a state where no potential difference is formed between the pixel electrodes and the common electrodes,
• the method comprising:
• preparing the first substrate including the pixel electrodes and the insulating layer including the openings;
• preparing the second substrate including the common electrode;
• applying a first alignment film material to a surface of the first substrate;
• applying a second alignment film material to a surface of the second substrate;
• forming the first alignment film by applying a photo-alignment treatment to the first alignment film material for making a pretilt angle of each of the liquid crystal molecules located near the flat areas zero;
• forming the second alignment film by applying a rubbing alignment treatment to the second alignment film material for making a pretilt angle of each of the liquid crystal molecules located near the second alignment film larger than zero;
• introducing a liquid crystal material containing a liquid crystal molecule and a polymerizable monomer between the first alignment film and the second alignment film;
• and
• forming the liquid crystal layer containing the polymer and the liquid crystal molecules by polymerizing the polymerizable monomer by emitting ultraviolet light to the liquid crystal material,
• wherein
• a thickness of the first alignment film is greater than or equal to 20 nm and less than or equal to 60 nm,
• a transmittance of the first alignment film for light having a wavelength of 450 nm is greater than or equal to 98%,
• the first alignment film material contains a photolysis component and a non-decomposition component,
• the photolysis component contains a first transparent component and a first coloring component,
• the non-decomposition component contains a second transparent component and a second coloring component,
• the first transparent component contains a polyamide acid or polyamide acid ester comprising a structure unit shown in formula (P1),
• the x1 of the formula (P1) is one of formula (X1-1) to formula (x1-4),
• the R1 of the formula (P1) is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and each of the R3 to the R23 of the formula (X1-1) to the formula (X1-4) is independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group containing a fluorine atom and having 1 to 6 carbon atoms or a phenyl group,
• a contained amount of the photolysis component is greater than or equal to 20 mol % but less than 50 mol % with respect to 1 mol of an entire structure unit of the first alignment film material,
• the first coloring component contains a polyamide acid or polyamide acid ester comprising the structure unit shown in the formula (P1),
• the Y1 of the formula (P1) of the first coloring component contains a polyamide acid or polyamide acid ester containing nitrogen, oxygen, fluorine or chlorine,
• a contained amount of the first coloring component is less than 10 mol % with respect to 1 mol of the entire structure unit of the first alignment film material,
• the non-decomposition component contains a polyamide acid or polyamide acid ester comprising a structure unit shown in formula (N1),
• the X2 of the formula (N1) is one of formula (X2-1) to formula (X2-22),
• a contained amount of the non-decomposition component is greater than 50 mol % but less than 80 mol % with respect to 1 mol of the entire structure unit of the first alignment film material,
• the second coloring component contains a polyamide acid or polyamide acid ester comprising the structure unit shown in the formula (N1),
• the Y1 of the formula (N1) of the second coloring component contains nitrogen (N), oxygen (O), fluorine (F) or chlorine (Cl),
• a contained amount of the second coloring component is less than or equal to 10 mol % of the entire first alignment film material,
• each of the Y1 of the formula (P1) and the Y1 of the formula (N1) is one of formula (Y1-a1) to formula (Y1-a2) and formula (Y1-b1) to formula (Y1-b81),
• the A1 of the formula (Y1-a2) is a single bond, an ester bond, an amide bond, a thioester bond or a divalent organic group having 2 to 20 carbon atoms, and the A2 of each of the formula (Y1-a1) and the formula (Y1-a2) is a hydrogen atom, a halogen atom, a hydroxyl group, an amino group, a thiol group, a nitro group, a phosphate group or a monovalent organic group having 1 to 20 carbon atoms, and the a of each of the formula (Y1-a1) and the formula (Y1-a2) is an integer from 1 to 4, and each of the b and the c of the formula (Y1-a2) is independently an integer from 1 to 2.