RESUMO
The surface localized polymer alignment (SLPA) method allows complete control of the polar pretilt angle as a function of position in liquid crystal devices. In this work, a liquid crystal (LC) cylindrical lens is fabricated by the SLPA method. The focal length of the LC lens is set by the polymerization conditions, and can be varied by a non-segmented electrode. The LC lens does not require a shaped substrate, or complicated electrode patterns, to achieve a desired parabolic phase profile. Therefore, both fabrication and driving process are relatively simple.
Assuntos
Eletrodos , Lentes , Cristais Líquidos/química , Cristais Líquidos/efeitos da radiação , Refratometria/instrumentação , Campos Eletromagnéticos , Desenho de Equipamento , Análise de Falha de Equipamento , Teste de Materiais , Conformação Molecular , Polímeros/química , Polímeros/efeitos da radiação , Propriedades de Superfície/efeitos da radiaçãoRESUMO
The mechanism for electric-field-induced segregation of additives, containing a polar group, in a host liquid crystal is proposed. It is shown that the polarity of an applied dc electric field, or the frequency of an ac electric field, strongly influences the segregation of reactive monomers containing an ester group. An explanation of this result is offered based on the association of dissolved ions with polar groups of the reactive monomers. This association is considered to cause these types of additives to drift to the cell surface in the presence of an external electric field. The described mechanism can be applied to the segregation of a broad range of additives in a liquid-crystal host.
