等离子体处理过的基板上液晶平行取向的两种模式

我们提出了一种用于液晶盒的新取向工艺,可以得到0或非0的预倾角。这项工艺是用定向的等离子体流倾斜辐照基板。我们用一个阳极层发射器(anodelagerthruster)作为等离子体辐射源,以产生层状的等离子体流。它适合于处理大面积基板,可以处理有机(聚合物)和无机(玻璃,ITO)层。等离子体流辐照可以得到两种类型的液晶取向:(1)最可及(择优)取向轴位于离子束方向和基板法线组成的入射平面上;(2)最可及取向轴垂直于入射面。随着照射总剂量的增加,取向方向可以从类型(1)向类型(2)转变。在第一种取向模式中,可以通过改变工艺参数,如入射角、离子流密度和离子能等来改变预倾角。第二种取向模式的特征是预倾角为0。第一种模式的方位锚泊能系数相对较弱(W=10-3 Erg/cm2),而第二种类型锚泊能很强(W>10-1 Erg/cm2),与摩擦聚合物基板相当。两种模式的取向特征可以用来产生满足所需参数的取向,和构图(pattern)液晶盒基板。这种工艺方法可以克服传统摩擦工艺的某些缺点。

Two Modes of LC Parallel Alignment on the Plasma Treated Substrates

We propose a new alignment procedure for liquid crystals cells that yields both zero and non-zero pretilt. This procedure is an oblique irradiation of the bounding substrates with the directed plasma flux.As a source of plasma irradiation we use an anode layer thruster producing sheet like plasma fluxes suitable to treat large-area substrates. Both organic (polymers) and inorganic (glass, ITO) layers can be treated. Plasma beam irradiation results in two types of LC alignment: (1) the easy axis in the incident plane formed by the direction of beam and the normal to substrate; (2) the easy axis perpendicular to the plane of incidence. By increasing the irradiation dose, one can change the alignment direction from the type (1) towards the type (2). In the first type of alignment, the pretilt angle con be controlled by changing parameters such as irradiation angle, ion current density, ion energy, etc. The second type of alignment is characterized by a zero pretilt. The azimutal anchoring energy coefficient is relatively weak (W=10-3 Erg/cm2) for the first type of alignment and strong (W>10-1 Erg/cm2, comparable to the rubbed polymer substrates) for the second type. The two-mode alignment feature can be used to generate alignment with desirable parameters as well as to pattern the LC cell substrates.The method is free of certain shortcomings known for the traditional rubbing technique.