Seung Beom Park

Pixel-Division Technology for High-Quality Vertical-Alignment LCDs

An innovative technology, charge-shared super patterned-electrode vertical-alignment (CS-SPVA), used for improving off-axis image quality within VA liquid crystal display (VA-LCD) is proposed. The CS-SPVA imposes different electric voltages with two or three subpixels automatically by a unique charge-sharing topology without increasing the number of data or gate bus lines, which results in significantly improved off-axis image quality without serious side effects. In particular, the three-subpixel-CS-SPVA shows the best off-axis image quality reported so far for the VA-type LCDs. The proposed technology may be the ultimate solution in overcoming the vulnerable point of VA-LCD for severe competition with alternative LCD technology.

Assessment of Image Quality Degraded by Tone Rendering Distortion

The tone rendering distortion index (TRDI), which assesses image quality degradation via the distortion within a display of the tone rendering curve (TRC), is introduced and investigated. The effect of the tone rendering distortion upon image quality is different from the effect of data-loss during image compression. The tone rendering distortion changes the lightness, hue and chroma, which results in degradation of an image into irregular patterns depending upon the shape of the distorted TRC. While peak-signal-to-noise ratio (PNSR) and color differences do not represent the image quality very well, the TRDI shows a strong agreement with the human-perceived image quality, despite its simplicity. The method is useful for developing new display technology as well as for refining the image processing within display systems.

34.3: A Novel Charge-Shared S-PVA Technology

A charge-shared super patterned-ITO vertical alignment (CS S-PVA) LCD mode is proposed. CS S-PVA controls the voltage ratio between two sub-pixels by a unique charge-sharing topology, resulting in improved off-axis image quality and transmittance increase without any side effects. Moreover, the new S-PVA LCD mode is free of image-sticking. Operating schemes and display performance of CS S-PVA are presented.

Ionic impurity control by a photopolymerisation process of reactive mesogen

Extremely low ion density, 10−8−10−11 molar fraction, which inevitably exists due to residual ion impurities even in a purified liquid crystal (LC) compound, can significantly influence the electro-optic response in LC devices. We found that the density of ionic molecules increased with the addition of various dopants including triphenylphosphine oxide (TPPO), molecules with the functional group of aldehyde, epoxide and so on into a nematic LC cell by observing the electrical response of the LC cells and that the irradiation of ultraviolet (UV) light accelerated the generation of ionic molecules, indicating degradation of organic materials. However, the addition of reactive mesogen (RM) compounds to the LC mixture significantly decreased the effective density of ions during and after the photopolymerisation process. The cured RM networks effectively captured the ion impurities during the photopolymerising process and their ion capturing ability was sustained even after completing the photopolymerisation process. This observation may provide a simple and useful way to control the effective ion density in a liquid medium down to extremely low levels.

Therapeutic effect of erythroid differentiation regulator 1 (Erdr1) on collagen-induced arthritis in DBA/1J mouse

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease, and multiple inflammatory cytokines are involved in RA pathogenesis. Interleukin (IL)-18, in particular, has a significant positive correlation with RA. In this study, we investigated the effect of erythroid differentiation regulator 1 (Erdr1), which is negatively regulated by IL-18, in an animal model of inflammatory arthritis, collagen-induced arthritis (CIA) in DBA/1J mice. Treatment of mice with recombinant (r)Erdr1 significantly suppressed the severity of arthritis, histologic features of arthritic tissue, and serum levels of anti-collagen autoantibodies (IgG, IgG1, IgG2a and IgM) in CIA. In addition, IL-18 expression was reduced in the affected synovium of rErdr1-treated mice. Interestingly, Erdr1 treatment suppressed migration in contrast to the pro-migratory effect of IL-18, indicating the therapeutic effects of Erdr1 on CIA through inhibiting synovial fibroblast migration. In addition, Erdr1 inhibited activation of ERK1/2, a key signaling pathway in migration of various cell types. Taken together, these data show that rErdr1 exerts therapeutic effects on RA by inhibiting synovial fibroblast migration, suggesting that rErdr1 treatment might be an effective therapeutic approach for RA.

57.3: Cost-Effective Pixel Structures for High Performance Mobile PVA LCDs

Two new pixel structures are proposed for use in high performance mobile PVA LCDs. The new structures enable use of a conventional polarizer for lowest possible cost. A 4.3″ prototype based on these techniques was built, achieving the worlds highest mobile display contrast ratio of 1200:1, while maintaining wide viewing angle with no loss of transmittance.