LCD controllers use familiar interfaces. Some controller ICs have more than one interface option that is user selectable. In many cases, the module JIYA supplies to you will already be internally configured to your interface requirements. 

All interface protocols must initialize the LCD module when it is first energized prior to use.

The most common LCD Module Interface Protocols are:

Parallel Interface

Serial Interface

Serial or Parallel Configuration to Microprocessor

TFT Interface Examples

As an LCD module manufacturer, JIYA welcomes discussions about various module design parameters, including different interface options.

Twisted Nematic (TN) and Super Twisted Nematic (STN) are the terms used to describe two types of liquid crystal displays. TN displays have a twist ( the rotation of the molecules from one plane of the display to the other) of 90 degrees or less. All passive direct drive , active matrix, and most passive low level (x2 to x32) multiplexed LCD's have a 90 degree twist.

As the name implies, Super Twisted Nematic LCD's have a twist that is greater than 90 but less than 360 degrees. Currently most STN displays are made with a twist between 180 and 240 degrees. The higher twist angles cause steeper threshold curves which put the on and off voltages closer together. The steeper thresholds allow multiplex rates greater than 32 to be achieved.

Pins, Heat Seals, and Elastomers are methods of mechanically interfacing the display to a printed circuit board.

	Pins are attached to the display to allow the user to either mount the display in a socket or solder it directly into a circuit board. From an end user standpoint, pins are the easiest to use since there is no requirement for a compression bezel or expensive heat seal bonding equipment. The pins are attached to the glass with a structural epoxy on the back. On the top, we apply an electrically conductive epoxy with an RTV overcoating.  Pins are the most reliable connection method.
	Heat seals are similar to flexible circuit boards with the difference being that the interface tabs are made of a conductive hot melt adhesive. Generally, particles such as carbon, gold, or silver are added to the adhesive to make it conductive. The pads of the heat seal are aligned with the pads of the display and a hot bar is brought down under pressure and the conductive adhesive is melted and bonded to the display. The adhesive is allowed to cool and an electrical bond is made with the display.
	Elastomers are silicon strips of alternating conductors and insulators. These materials are generally soft and compliant and can be easily compressed between the display and circuit board. Elastomers require a bezel to squeeze the display and circuit board together.

Ordinary light from an incandescent bulb or from the sun is randomly polarized, that is, it includes waves that are oriented in all possible directions.

A polarizer is a material that is used to convert a randomly polarized ("un-polarized") beam of light into a polarized one, oriented in such a way that light with E2 (electric vector) along the x axis is absorbed, while the E1 along the y axis is transmitted. What emerges is that component of the original wave which had the y direction polarization. In the example above, the polarizing direction is along the y axis.

Positive image reflective liquid crystal displays have a polarizer applied to the front of the display and a reflector applied to the rear of the display. The liquid crystal molecules control the polarization state of beam of light polarized by the front polarizer. Controlling the orientation of the liquid crystal molecules will change the polarization of the beam.

As the polarized light from the front polarizer passes through an un-energized display, it will be rotated 90 degrees by the liquid crystal and either absorbed or passed by the rear polarizer. When the display segment is energized, the liquid crystal will rotate in the direction of the electric field and no longer rotate the polarized beam of light. Again, depending on the direction of the analyzer, the light will be either absorbed or passed. In the case of a positive image reflective display, this would produce a dark character on a light background. It is important to note that twisted nematic liquid crystal displays must have a polarizer applied to both the front and rear surfaces for them to function as useful devices.