A liquid crystal display device includes a lower substrate including a light blocking layer, a color filter including a light blocking layer, and an ITO pixel electrode; an active circuit portion including a liquid crystal layer, a thin film transistor, and a capacitor layer; and an upper substrate including an ITO pixel electrode.
The light blocking layer blocks uncontrolled light transmitted out of a transparent pixel electrode of a substrate and thus prevents contrast reduction due to light transmitted through a thin film transistor. Red, green and blue colored layers transmit light with predetermined wavelengths of white light and display colors.
The light blocking layer is generally manufactured by a pigment dispersion method. The pigment dispersion method includes coating a transparent substrate with a colorant-containing photopolymerizable composition, exposing the coating to provide a pattern by thermal curing, and removing non-exposed portions with a solvent.
However, when a photosensitive polyimide or phenol-based resin is used in the pigment dispersion method as a binder resin, high heat resistance may be obtained but sensitivity is lowered and an organic solvent is required as a development solvent. A photoresist using an azide compound has low sensitivity and heat resistance and may be affected by oxygen during exposure.
Also, an acrylic-based resin can have good heat resistance, shrinkage-resistance, chemical resistance, and the like, but reduced sensitivity, developability, and close contacting (adhesion) properties. Since black pigments are included in a large amount in order to adjust optical density of a light blocking layer, sensitivity, developability, and close contacting properties may be significantly deteriorated.
USPTO Backgrounds
USPTO Backgrounds