Liquid crystal display device and method of producing the same

1. A liquid crystal display device comprising:

a pair of substrates arranged facing each other;

a liquid crystal seated between the pair of substrates; and

a photo-cured product having a side chain structure for controlling an alignment of the liquid crystal, the photo-cured product being formed near interfaces to the pair of substrates upon polymerizing a polymerizable component containing a polyfunctional monomer having a symmetrical structure mixed in the liquid crystal with light,

wherein a ratio of the polyfunctional monomer remaining in the liquid crystals is not larger than 20% by weight relative to a total amount of unreacted monomers remaining in the liquid crystal.

2. A liquid crystal display device according to claim 1 , wherein the polyfunctional monomer includes a ring structure.

3. A liquid crystal display device according to claim 1 , wherein the polyfunctional monomer includes a bifunctional monomer having a flexible structure.

4. A liquid crystal display device according to claim 1 , wherein the polyfunctional monomer has a structure represented by the chemical formula (1),

wherein X is an acrylate group or a methacrylate group, A represents the chemical formula (2),

the chemical formula (3),

or the chemical formula (4),

and B represents the chemical formula (5),

or the chemical formula (6),

and m and n are 0 or integers of 1 or larger.

5. A liquid crystal display device according to claim 4 , wherein m and n are 0 or 1, respectively.

6. A liquid crystal display device according to claim 1 , wherein an alignment film for controlling the alignment of the liquid crystal and formed by coating is not formed near the interfaces between the pair of substrates and the liquid crystal.

7. A liquid crystal display device according to claim 1 , wherein the liquid crystal is sealed by the drop injection method.

8. A liquid crystal display device according to claim 1 , further comprising a plurality of column spacers formed on the substrates to maintain a cell gap between the pair of substrates.

9. A liquid crystal display device according to claim 1 , wherein:

the liquid crystal has a negative dielectric anisotropy and is nearly vertically aligned to the substrate surfaces when no voltage is applied; and

a structure for regulating the alignment is formed on at least either one of the pair of substrates to regulate a direction of alignment of the liquid crystal when a voltage is applied.

10. A method of producing a liquid crystal display device, comprising the steps of:

sealing, between a pair of substrates, a liquid crystal into which a polymerizable component containing a polyfunctional monomer having a symmetrical structure is mixed;

polymerizing the polymerizable component by irradiating the liquid crystal with light cutting off a region of short wavelengths which are shorter than 310 nm; and

forming a light-cured product having a side-chain structure near interfaces to the pair of substrates,

wherein a ratio of the polyfunctional monomer remaining in the liquid crystals is not larger than 20% by weight relative to a total amount of unreacted monomers remaining in the liquid crystals.

11. A liquid crystal display device according to claim 1 , wherein the polyfunctional monomer has a structure that can be polymerized with light of a wavelength of not shorter than 310 nm with the liquid crystal as a solvent; and

an intensity at the wavelength of 310 nm is about 0.02 to about 0.05 mW/cm 2 .

12. A liquid crystal display device according to claim 1 , wherein the side chain structure comprises an alkoxyl group.