-T-

Term (Acronym) [units]: Definition

Tape Automated Bonding (TAB): A process that places bare chips on a printed circuit board by attaching them to a polyimide film. The film is moved to the target location on the PCB, then the leads are cut and soldered to the board. Can also be used to attach chips to flexible cable.

TCON Board: The printed circuit assembly that includes a display’s timing controller chip. Not an official term; closer to industry slang.

Thermal Management: Processes employed to dissipate heat generated by electronic devices to improve reliability and prevent premature failure.

Thick-Film Dielectric Electroluminescent (TDEL): The technology being used by iFire in their TV-sized flat-panel EL displays.

Thin Film Transistor (TFT): A transistor used in high-performance active matrix LCDs. In TFT technology, one or more transistors are used to control each individual subpixel.

Threshold Voltage (V_th): The voltage level where enough electrons accumulate in the channel of a TFT to turn the device on. One of the problems in developing reliable active-matrix backplanes for OLEDs is that this voltage gradually changes significantly over time, which radically changes the characteristics of the display.

Timing Controller (TCON): An IC used in all LCDs to calculate the correct timing of signal generation, which is sent to the level shifters to ramp the proper display drive voltage.

TN+Film: A term that identifies standard monitor-size TN LCDs modified with compensation films to enhance their viewing angles and thus compete more effectively with monitor LCDs that use MVA, PVA or S-IPS wide-angle-viewing technology. While the viewing angles are wider than standard TN, they’re not as wide as the other technologies. However, TN+Film is lower cost and the angles are good enough for some users.

Top-Emitting OLED (TOLED): An OLED constructed such that the light is emitted through the top of the structure rather than through the bottom substrate as is usually the case. Top emission results in an aperture ratio of about 70%, compared with 40% for bottom-emission.

Total Available Cycle Time (TACT): Process time per substrate. This is a critical measure of manufacturing efficiency in the display industry.

Total Available Market (TAM): The sum of the annual unit sales of all competing products in a market.

Touch Panel: Another term used in place of touch screen.

Touch Screen: A subsystem that returns the coordinates of the location that a user is touching with a finger or stylus within the active area. There are six touch technologies in common use: resistive, surface capacitive, projected capacitive, infrared, surface acoustic wave (SAW) and acoustic pulse recognition (APR).

Touch Screen Controller: A microcontroller that manages the interaction between the touch screen subsystem and the rest of the computer. Advanced controllers support multiple touch technologies and sensors from multiple vendors without making any hardware or software changes.

Transflective: A type of LCD that’s a blend of transmissive and reflective. The pixels are partially silvered (reflective) so that a portion of the ambient light is reflected back to the user when the ambient light is high (outdoors). Indoors, the LCD functions as a normal transmissive display, with the backlight being transmitted through the transparent portion of the pixels. Performance is a compromise; neither transmissive mode nor reflective mode is as good as a dedicated-architecture LCD. It’s also possible to create a transflective LCD by adding a transflector sheet between the backlight and the LCD cell, but performance is almost always unsatisfactory.

Transmissive: A type of LCD where all of the backlight is transmitted through transparent pixels. When used outdoors, a transmissive LCD must be enhanced to reduce reflections in order for the image to be readable.

Transmissivity: The percentage of light that is transmitted through a layer or assembly. For example, the transmissivity of standard resistive touch screens is about 80%, which means that up to 20% of the light is reflected back to the user, drastically lowering the contrast of the displayed image.

Transparent: Capable of transmitting light without diffusion or attenuation so that objects or images can be seen as if there were no intervening material. The degree of transparency is described by the transmissivity in percent.

Transparent OLED (TOLED): An OLED that uses a transparent contact structure so that the entire display becomes transparent, with light emission possible from the top and bottom or just from the top.

Tri-Acetate Cellulose (TAC): A film used as a base material (substrate) for polarizers.

True Color: A Microsoft term for 24-bit color depth (256 shades of red x 256 shades of green x 256 shades of blue = 16.7 million colors).

Twisted Nematic (TN): The standard mode of most LCDs; used in many applications including laptop LCDs and low-end monitors. The liquid crystal molecules in a TN display are oriented 90 degrees away from each surface of glass. TN’s primary disadvantage is the relatively poor viewing angle (although film compensation can be added to broaden the angles).

Twisted Nematic Liquid Crystal Display (TNLCD): See Twisted Nematic (above).