Optically Compensated Bend (OCB)

OCB is a technology that realizes high-performance capabilities comparable to those of cathode ray tube (CRT) displays, offering fast response time and wide viewing angles which have been the challenge of conventional liquid crystal displays (LCDs). Toshiba Mobile Display Co., Ltd. (TMD) has become the first manufacturer in the world to realize mass production of OCB LCDs, in 2004. TMD has been applying OCB technology in both amorphous silicon (a-Si) TFT LCDs and low-temperature poly-silicon (LTPS) TFT LCDs. In addition, TMD is also mass-producing the world's largest-size OCB LTPS TFT LCD panels. This section describes the structure, characteristics, and range of applications of OCB LCD panels.

OCB technology

Characteristics of OCB

• The world's highest level of fast-response performance
• The industry's top-class in wide viewing angle
• Smooth display images even at low temperature of -20°C

The world's highest level of fast-response performance

The response time of a LCD depends on the speed of changes in alignment of the rod-like liquid crystal molecules caused by varying the applied voltages. The OCB LCD and its inherent technology is characterized by the arrangement of the liquid crystal molecules. In the conventional LCD, the liquid crystal molecules are arranged horizontally or vertically against the glass substrate, while in the OCB LCD, the liquid crystal molecules are aligned to form an arch pattern (bend-aligned). The bend-aligned liquid crystal molecules cause the alignment to change when exposed to voltages, and when the flow of liquid crystals is generated, the bend accelerates the alignment changes. Due to the assisting effect of the liquid crystal flow, OCB technology allows for very fast response times. TMD has succeeded in integrating our proprietary liquid crystal driving technology and backlight control technology into the fast-response characteristics of OCB technology, thereby realizing the world's highest level of moving picture performance in an LCD panel.

The industry's top class in wide viewing angle

Conventional LCD panels were limited in the angles of visibility, since some light is leaked when viewed from any direction other than the front, thus changing color tones and decreasing contrast. However, OCB technology enables a wide viewing angle of 176 degrees in all directions, which is comparable to that of a CRT, without loss of brightness, even when viewed vertically, horizontally, and diagonally, owing to the self-compensating effect of viewing angle based on the OCB bend-alignment and the high-precision optically-compensated design.

Smooth display images even at low temperature of -20°C

The fast-response OCB technology has also solved the problem of deteriorated response time at low temperatures inherent in the case of LCD panels. OCB technology has succeeded in achieving response speeds even at -20°C equivalent to those attained in conventional LCD panels at room temperature. As a result, an OCB LCD panel can provide smooth display images even upon start-up of a car engine in the winter season when applied as a vehicle-mounted display panel.

Range of applications for OCB LCDs

At present, OCB LCD panels have been applied for broadcasting equipment monitors. The panels allow for clear and crisp graphic displays in the process of picture taking and editing, on cameras required to survive in frigid temperatures and other professional uses for image processing. OCB technology will further expand its range of applications, taking advantage of fast-response time and other characteristics related to offering high-quality pictures.