Liquid crystal display device

Claim 1

A projection type liquid crystal display device comprising: a first polarizer; a second polarizer; first and second transparent insulating substrates arranged in parallel to each other; a liquid crystal display cell arranged between said first and second polarizers for displaying an image thereon, said liquid crystal display cell including a liquid crystal layer arranged between said first and second transparent insulating substrates; first transparent electrodes formed on an inner surface of said first transparent insulating substrate; second transparent electrodes formed on an inner surface of said second transparent insulating substrate so as to cross said first transparent electrodes; switching means, including a transistor arranged on an inner surface of said first transparent insulating substrate, for controlling an applied voltage between said first and second transparent electrodes so as to drive picture elements defined at the crossings between said first and second transparent electrodes, said switching means including a gate electrode of the transistor formed on the inner surface of said first transparent insulating substrate, an electrically insulating film formed on said gate electrode, a semiconductor film formed on said electrically insulating film and a source electrode and a drain electrode of the transistor formed on said semiconductor film, wherein thickness of said semiconductor film is greater than thickness of said gate electrode; a light source, arranged on the side of an outer surface of said second polarizer, for emitting light through said second polarizer, said second transparent insulating substrate, said liquid crystal display cell, said first transparent insulating substrate and said first polarizer toward a display screen arranged on the side of an outer surface of said first polarizer, said emitted light having a large enough intensity so as to project an image displayed on said liquid crystal display cell onto said display screen so that said projected image can be viewed; and shading means arranged on the second transparent insulating substrate for shading light incident to at least a rim portion of said first transparent electrode and said switching means; wherein the respective polarization axes of said first and second polarizers are set so that the light emitted from said light source is prevented from transmitting through said second polarizer, said liquid crystal display cell and said first polarizer, at the time of the application of a predetermined voltage between said first and second transparent electrodes, and the light therefrom is allowed to transmit therethrough at the time of the application of zero voltage therebetween.