The present invention provides a projection type liquid crystal display device capable of achieving a high contrast ratio without causing optical leakage on boundary wavelength regions of three color light components in the case of a black display. The projection type liquid crystal display device is...http://www.google.se/patents/US7148936?utm_source=gb-gplus-sharePatent US7148936 - Color-separation/synthesis optical system with particular cut-off wavelengths and emission-side polarizer and projection type liquid crystal display device using the same
