Liquid crystal display with holographic diffuser and prism sheet on viewer side

A backlit normally white twisted nematic liquid crystal display capable of providing an image to a remotely positioned viewer, comprising:

• a display panel including a plurality of pixels, each said pixel being comprised of a pair of driving electrodes sandwiching a twisted nematic liquid crystal layer therebetween;
• a backlight for directing at least partially collimated light toward said display panel;
• an optical system affixed to said panel including a holographic diffuser and a refracting means disposed on the viewer side of said twisted nematic liquid crystal layer, said optical system providing said display with a contrast ratio of at least about 70:1 along the 0.degree. vertical viewing axis at horizontal viewing angles up to about .+-.60.degree., and whereby said refracting means maintains the resolution of the displayed image;
• and
• wherein said display includes means for obtaining a specular 30.degree. reflectance of less than about 2%, and a diffused 30.degree. reflectance of less than about 5%.

A backlit liquid crystal display comprising:

• a backlight for directing rays of light toward a display panel;
• said display panel including a liquid crystal layer and means for applying a voltage to said liquid crystal layer;
• a holographic diffuser and a faceted film means for substantially collimating ambient light directed toward said liquid crystal layer, said diffuser and said faceted film means affixed to said display panel on the viewer side of, said liquid crystal layer, wherein said display panel when white substantially collimated light is directed toward said panel from said backlight has at least the following viewing characteristics:
• a) a specular reflectance at about 0.degree. vertical, 30.degree. horizontal of less than about 2.0%;
• b) a diffused reflectance at about 0.degree. vertical, 30.degree. horizontal of less than about 4%;
• and
• c) a contrast ratio of at least about 60:1 at viewing angles of one of:
• (i) about 0.degree. vertical, .+-.60.degree. horizontal;
• and (ii) about 0.degree. horizontal, .+-.40.degree. vertical.

A backlit liquid crystal display for displaying an image having improved viewing characteristics to a viewer, the display comprising:

• a collimating backlight for directing substantially collimated light toward a display panel, said display panel including:
• (i) a twisted nematic liquid crystal layer sandwiched between a front polarizer and a rear polarizer, said front polarizer being located on the viewer side of said liquid crystal layer;
• (ii) electrodes for applying a voltage across said liquid crystal layer;
• (iii) a light redirecting or redistributing means disposed on the viewer side of said liquid crystal layer, said light redirecting or redistributing means for enabling:
• (a) substantially no backscatter in both transmission directions so as to reduce reflections in both directions;
• and
• (b) in the transmission direction from said backlight toward the viewer, said light redirecting means diffusing light emitted from said backlight over a wide range of angles toward the viewer so as to improve contrast;
• and
• wherein as a result of said light redirecting or redistributing means, said display has a specular 30.degree. reflectance of less than about 0.3%, a diffused 30.degree. reflectance of less than about 1.2%, and a contrast ratio at viewing angles of about 0.degree. vertical, .+-.30.degree. horizontal, of at least about 60:1.

A method of displaying an image to a viewer using a twisted nematic liquid crystal display with reduced reflection and an enlarged viewing zone, the method comprising the steps of:

• providing a collimating backlight;
• emitting collimated light from the backlight toward the twisted nematic liquid crystal display;
• selectively applying voltage across a liquid crystal layer in the display by way of electrodes;
• redistributing the light after it exits the liquid crystal layer using a light redistributing system disposed on the viewer side of the liquid crystal layer;
• substantially eliminating backscatter in both transmission directions using the redistributing system so as to reduce reflections in both directions;
• diffusing light traveling from the liquid crystal layer toward the viewer over a wide range of angles using the redistributing system in order to improve contrast;
• as a result of the distributing system, displaying an image to the viewer having a contrast ratio at viewing angles of about 0.degree. vertical, .+-.30.degree. horizontal, of at least about 60:1;
• and.
• as a result of the distributing system, reducing specular 30.degree. reflectance to less than about 0.3% and diffused 30.degree. reflectance to less than about 1.2%.