LCD C/D – LCD Driver and Controller

The twisted nematic field effect in liquid crystals was patented on December 4, 1970 by Hoffmann-LaRoche in Switzerland and led to the development of TN-LCD’s and numerous other products in the early 70s. Twisted nematic displays contain liquid crystal elements which twist and untwist at varying degrees to allow light to pass through. When no voltage is applied to a TN liquid crystal cell, the light is polarized to pass through the cell. In proportion to the voltage applied, the LC cells twist up to 90 degrees changing the polarization and blocking the light's path. By properly adjusting the level of the voltage almost any grey level or transmission can be achieved. It is easy to understand that large TN-LCD’s use in Graphing Calculators, Pocket Dictionaries and Personal Digital Assistants (PDAs) with thousands and even ten-thousands of pixel need complex drivers to control every single pixels. Semiconductor manufacturers like Epson, Hitachi , Sharp and Toshiba pioneered the development of drivers in CMOS technology for modern displays and today we know different approaches:

External Drivers:

Include no Display RAM, connected to LCD Controller. Available as Column, Row, or selectable Column / Row driver.  

LCD Drivers with built-in RAM:

Row drivers provide the timing for the display and and control the column drivers. Column drivers integrate bit-mapping Display RAM, some drivers, for instance the Toshiba T6A04 / T6K04 used in most TI-83 Plus / TI-84 Plus graphing calculators, combine Row and Column drivers.

LCD Controller:

Provide timing, internal or external Display RAM and use external drivers.

LCD Controller/Driver:

Provide timing, Display RAM and integrated drivers in a single-chip package.

Display Driver

Display Controller

Novatek Microelectronics Corp., headquartered in Hsinchu Science Park, Taiwan, is a leading fabless chip design company specializing in the design, development and sales of a wide range of display driver ICs & SoC solutions.
July 2007: Novatek is recognized as the largest supplier of Display Driver IC for large-size LCD panels, as well as the world's second largest supplier of Display driver IC by world's leading research company - iSuppli.

SMOS Systems Inc., headquartered in San Jose, CA, started already in 1983 the marketing and sales of low power, advanced CMOS integrated circuits developed and manufactured by Seiko Epson Corporation of Japan.

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