Liquid crystal display device with at least 7.degree. C. liquid crystal to isotropic phase transition temperature difference and method of making

A liquid crystal display device comprising a pair of electrode substrates at least one of which is transparent, a display medium having a liquid crystal region surrounded by a polymer region, and a plurality of pixels, the display medium being interposed between the pair of substrates,

• wherein a difference between an upper limit value and lower limit value of a phase transition temperature between a liquid crystal phase and an isotropic liquid phase of a liquid crystal composition constituting the liquid crystal region is 7.0.degree. C. or more, and
• a polymer constituting the polymer region is formed from a mixture of polymerizable material having a glass transition temperature of 50.degree. C. or more and a liquid crystalline polymerizable material.

A method for producing a liquid crystal display device comprising the steps of:

• injecting a mixture containing a liquid crystal composition and a polymer material between a pair of electrode substrates at least one of which is transparent, the liquid crystal composition having a difference between an upper limit value and a lower limit value of a phase transition temperature between a liquid crystal phase and an isotropic liquid phase of 7.0.degree. C. or more;
• and
• causing phase separation of the mixture by polymerizing the polymerizable material to form a polymer region and a liquid crystal region surrounded by the polymer region.