Liquid crystal display with twisted nematic dimmer

A method for selectively controlling light entering an LCD display panel from a backlight, the LCD display panel comprising a liquid crystal section and a rear polarizer positioned between the liquid crystal section and the backlight, the method comprising the steps of:

• positioning a polarizing element between the backlight and the LCD display panel;
• positioning a twisted nematic LCD cell between the polarizing element and the rear polarizer of the LCD display panel;
• and
• variably applying an electric voltage across the twisted nematic LCD cell to selectively control the intensity of the light passing through the twisted nematic LCD cell and entering the LCD display panel.

A backlit liquid crystal display apparatus comprising:

• an LCD display panel;
• a light source positioned behind the LCD display panel and operative for illuminating the LCD display panel;
• and
• a dimmer positioned between the LCD display panel and the light source, the dimmer operative for variably controlling the illumination of the LCD display panel, wherein the dimmer comprises a brightness-enhancing polarizing element and a twisted nematic LCD cell positioned between the polarizing element and the LCD display panel,
• wherein the twisted nematic LCD cell comprises a liquid crystal material having a plurality of distinct planes of liquid crystal molecules, including first molecules of a first plane, last molecules of a last plane, and intermediate molecules of one or more intermediate planes that are positioned between the first plane and the last plane, and
• wherein the first plane molecules are oriented at an angle to the last plane molecules in response to a first voltage being applied across the twisted nematic LCD cell, the first plane molecules, the intermediate plane molecules, and the last plane molecules are oriented in alignment with each other in response to a second voltage being applied across the twisted nematic LCD cell, and the first plane molecules, the intermediate plane molecules, and the last plane molecules are oriented in partial alignment with each other in response to a voltage between the first voltage and second voltage being applied across the twisted nematic LCD cell.

A backlit liquid crystal display apparatus comprising:

• an LCD display panel having a liquid crystal section and rear polarizer positioned behind the liquid crystal section, the rear polarizer having a polarity;
• a light source positioned behind the LCD display panel and operative for illuminating the LCD display panel;
• and
• a dimmer positioned between the LCD display panel and the light source, the dimmer comprising a polarizing element and a twisted nematic LCD cell positioned between the polarizing element and the rear polarizer, the polarizing element having a polarity that is in alignment with the polarity of the rear polarizer, the twisted nematic LCD cell comprising a liquid crystal material including first molecules of a first plane, last molecules of a last plane, and intermediate molecules of one or more intermediate planes that are positioned between the first plane and the last plane,
• wherein the first plane molecules are oriented perpendicular to the last plane molecules and to the polarity of the rear polarizer or the polarizing element in response to a first voltage being applied across the twisted nematic LCD cell,
• wherein the first plane molecules, the intermediate plane molecules, and the last plane molecules are oriented in alignment with each other and with the polarity of the rear polarizer and the polarizing element in response to a second voltage being applied across the twisted nematic LCD cell, and
• wherein the first plane molecules, the intermediate plane molecules, and the last plane molecules are oriented in partial alignment with each other and with the polarity of the rear polarizer and the polarizing element in response to a voltage between the first voltage and second voltage being applied across the twisted nematic LCD cell,wherein the dimmer is operative for variably controlling the illumination of the LCD displaypanel.