Color filter manufacturing method of liquid crystal display device

The colour filter, especially for a LCD display, has a substrate (21) with a register code pattern (23') over a given area to position a mask over the substrate, with a step difference of a given value to give diffused light on illumination by a light beam. Also claimed is a mfg. process for the colour filter with a register code pattern (23') with a step difference to give diffused light from a light beam (27) to a substrate (21). The mask, covered by the register code pattern (23') allows illumination of the photo varnish layer (24) on the substrate (21), using a blue or green photovarnish layer (24). The colour filter is in a layered structure with an initial coloured photo layer over one section of the substrate (21). The register code pattern (23') is over a further section of the substrate (21) to give diffused light from a laser beam (27) with a determined step difference to the first coloured photo layer. A second coloured photo layer (24) is on the substrate(21) covered by the register code pattern (23')