A liquid crystal composition is provided and includes: at least one kind of liquid crystal R exhibiting a liquid crystal phase having a positive birefringence property; and at least one kind of liquid crystal D exhibiting a liquid crystal phase having a negative birefringence property. Each refractory metal material is a conductive material containing a refractory metal and an impurity. A surface of the cage contacting the vertebrae has an undulating shape for limiting sliding of the cage in a plane parallel to the vertebrae faces. Additional aspects may include features that enable state by state pumping, for example, circuitry that avoids cascaded short circuits among pump stages. The leg frames 1 and 2 are inverted-square-bottomed-\u201cU\u201d-shaped and set in outer frames 1 and 2.