High Brightness TFTs
TFT (thin-film-transistor liquid-crystal) displays can generate between 64K and 64M unique colors. Most can display videos and produce high contrast images and characters.
Sunlight Readable TFT Modules (High Brightness TFT Displays) are found in outdoor applications that must compete with the sun. Applications include store windows to catch people’s attention, dashboards of cars, boats, aviation and even farm equipment.
High brightness modules ensure that sunlight and other sources of light will not reduce the screen’s visibility.
HOW BRIGHT OF A TFT DO YOU NEED?
Indoor applications require between 200 Nits to 400 Nits, but sunlight readable products require a minimum of 700 Nits although 1K Nits and higher is recommended.
One Nit is equal to the candela per square meter (cd/m 2).
INCREASING BRIGHTNESS:
Some standard displays are built to reach 1k nits. If your display is not bright enough, you can add more LEDs to the backlight or increase the driving current to achieve your desired brightness.
The downside to increasing current or adding more LEDs is that the display requires more power—a major setback for battery powered products. Additionally, the heat produced by the backlight has potential to overheat the TFT.
It is possible to increase the display’s brightness without a large jump in heat by using LED backlight drivers with PWM (Pulse Width Modulation) brightness control.
TFTs can be modified to increase their brightness to the level needed for your new design.
ADJUSTABLE BRIGHTNESS:
Not every application requires full brightness all the time. Aviation dash boards need the flexibility to increase brightness in direct sunlight and decrease brightness at night to avoid blinding the pilot.
TFT displays can adjust to meet the needs of the end user.
TFT INTERFACES:
All standard TFTs contain built in controllers with various interfaces including SPI, parallel, LVDS, RGB and the increasingly popular HDMI (High-Definition Multimedia Interface).
TFT DISPLAYS WITH TOUCH SCREENS:
Touch screens (panels) can come preinstalled, or you can add a one to an existing TFT.
The two most common types of touch panels are capacitive and resistive.
Capacitive Touch Panel
Capacitive touch panels offer higher clarity than resistive touch panels and are not affected by the outside elements. Capacitive touch panels are coated with a thin material that stores electrical charges, like a capacitor, and are made up of two layers of glass, each coated with Indium Tin Oxide (ITO). When this type of surface is touched, a small charge is drawn to the point of contact. The circuits then relay this information and send it to the controller to be processed.
Resistive Touch Panel
Resistive touch screen panels are coated with thin metallic layers. These layers have properties that are both electrically conductive and resistive. The top layer has an electrical charge going from top to bottom, while the second layer has an electrical charge going from side to side, with a thin air gap in between each layer. When touched by an object, the change in current is registered and sent to a controller to be processed.
Resistive is cheaper and easier to integrate but will reduce the display’s brightness by a few percent.
TFT SIZES:
Focus LCDs carries standard TFTs in stock, ranging from 1.3 inches to 10 inches in size. Most samples can ship the same day they are ordered.