Yoji Ito

Review of viewing‐angle compensation of TN‐mode LCDs using WV film

— Wide-view (WV) films for TN-mode LCDs, which optimize the optical parameters of the polymerized discotic material (PDM) layer and cellulose triacetate (CTA) have been developed. The development concept of the WV film and realization of its concept in the past and for the future will be reviewed. In particular, the discotic molecular alignment control enabled the improvement of the contrast ratio at oblique viewing angles of TN-mode LCDs. In addition, color shifts at oblique angles are important for large-screen TN-mode LCD monitors and LCD-TV sets. To improve the color-shift problem, new technologies have been developed.

11.1: Invited Paper: Review of Viewing Angle Compensation of TN‐Mode LCDs Using WV Film

We developed WV films for TN-mode LCDs, which optimized optical parameters of the polymerized discotic material (PDM) layer and cellulose triacetate (CTA). We will review the development concept of WV film and realization of its concept before now and from now. Especially the discotic molecular alignment control enabled us to improve the contrast ratio at oblique viewing angles of TN-mode LCDs. In addition, color shifts at oblique angles are important for large screen size TN-mode LCD monitors and LCD TV sets. To improve this color shift problem, we have developed new technologies.

6.1: High Performance VA‐LCD Compensation Film Made with Environmentally Friendly Material for VA‐LCD

We have successfully developed a novel compensation film, EVE-film Environmental friendly film for VA-LCD performance Enhancement, which improves VA-LCD performance with less environmental burden. We satisfactorily realized optical designs of EVE-film by controlling the internal haze, wavelength dispersion, and optical anisotropy, with innovative casting process. After all our efforts, VA-LCD using EVE-film exhibited 13% higher contrast and a color-shift significantly better than our previous compensation film.

55.1: Development of Low Haze VA Compensation TAC Film and Proposal of Compensation Film Arrangement for Improving CR in VA Panel

We developed a low-haze VA compensation TAC film for high contrast ratio VA-LCDs, by reducing micro anisotropic nonuniform structure inside the stretched TAC film. Moreover, we found that the arrangement of our low-haze VA compensation TAC film as a single compensator on the front side of VA-LCDs with color filter on TFT arrays realizes more than 10 % higher on-axis contrast ratio than that of conventional compensation films as double compensator.

A novel WV film for fast-response-time OCB-LCD

We have successfully developed and commercialized an optical compensation film for OCB-LCD mode (OCB-WV film). OCB-LCD mode is known to have a very fast optical response time and makes next-generation fast-response LCD-TVs possible and free from image blurring. The OCB-WV film, which has a structure composed with TAC (triacetyl cellulose) film and PDM (polymerized discotic material) layer, can realize the wide viewing angle of OCB-cell. In order to provide the best performance of OCB-cell, we optimized an optical parameter of not only WV film but also OCB cell by a numerical simulation. In this paper, we will discuss a concept of its optimization, which provide excellent results of a numerical simulation.