Level optical colour filter prodn. from negative light-sensitive coat - by opt. repeated exposure and toning, total exposure through substrate and coating with transparent powder before heating, useful for LCD

摘要

Prodn. of optical colour filters comprises: (a) giving a substrate (I) with a negative-working, tonable light-sensitive coat (II), which can be removed by heat treatment; (b) selective exposure; (c) toning with a coloured powder (III), consisting of a thermoplastic or fusible colourant or contg. a colourant and a thermoplastic binder (IIIA); (d) opt. repeating steps (b) and (c) for other colours; and (e) heating the powder pattern below 240 deg C.. The novel features are that (1) (II) is given a total exposure through (I) before step (e); and (2) the coated side of (I) with the powder image is treated with a finely-divided transparent material (IV). USE/ADVANTAGE - The technique is esp. useful for making single or multi-colour filters for coloured LCDs. A black matrix can be produced at the same time. Total exposure through the back increases the amt. of (IV) taken up by (II). (IV) counter-reactors unevenness in the surface, stabilises the filter and back matrix and gives a chemically uniform surface, which facilitates following stages, e.g. application of a levelling coat, which can be thinner than the usual 10 microns.