11.2: Improved Contrast Ratio in IPS‐Pro LCD TV by Using Quantitative Analysis of Depolarized Light Leakage from Component Materials

Utsumi, Yuka; Takeda, Shintaro; Kagawa, Hiroyuki; Kajita, Daisuke; Hiyama, Ikuo; Tomioka, Y.; Asakura, T.; Shimura, Masato; Ito, Masahiro; Miyazaki, Kaori; Ono, Kyosuke

doi:10.1889/1.3069379

Cited by 15 publications

(13 citation statements)

References 4 publications

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“…The origins of depolarization are rather complicated; they may come from the diffraction effect of patterned thin-film transistors (TFTs) and electrode, light scattering from LC layer and color filter (CF) array, misalignment of crossed polarizers, and rubbing scratches, etc. [4][5][6][7][8] Fig. 2 schematically depicts some of these factors.…”

Section: Origins Of Depolarizationmentioning

confidence: 99%

“…Moreover, these physical origins make different contributions to different LC modes. For example, in FFS and in-plane switching (IPS) modes, scattering effect from LC director's thermal fluctuation contributes 50%-60% to the total depolarization effect (also known as degree of imperfection), while CF pigment scattering makes 30%-40% [5,7]. But in VA mode, LC scattering is greatly reduced, thus CF scattering turns out to be the dominant factor [10].…”

Section: Origins Of Depolarizationmentioning

confidence: 99%

“…To improve CR, increasing the polarizer thickness is a straightforward approach. However, more evidences reveal that polarizer is no longer the limiting factor [4][5][6][7]. In fact, it is fairly easy to get CR > 100,000:1 with two high-quality crossed polarizers, but the final CR of an LCD is still limited to 5,000:1, which is mainly governed by the depolarization effect inside the LCD panel.…”

Section: Introductionmentioning

confidence: 99%

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P‐153: High Contrast Ratio LCD with an In‐cell Polarizer

Chen

Tan

et al. 2018

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We develop a rigorous model to simulate an LCD's contrast ratio (CR) and viewing angle by considering the depolarization effect. To improve CR, an in-cell polarizer is added between LC layer and color filter array. The obtained maximum CR of a multi-domain vertical alignment LCD is boosted to > 20,000:1. KeywordsLiquid crystal display; Contrast ratio; In-cell polarizer. P-153 / H. Chen • SID 2018 DIGEST

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Section: Origins Of Depolarizationmentioning

confidence: 99%

Section: Origins Of Depolarizationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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P‐153: High Contrast Ratio LCD with an In‐cell Polarizer

Chen

Tan

et al. 2018

Symp Digest of Tech Papers

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“…However, such a mechanical rubbing process cannot ensure the perfectly uniform alignment of molecules, and random defects deteriorate the black quality. It has recently been reported that a contrast ratio of 1,500:1 has been achieved for IPS-mode panels through the use of an improved rubbing process and materials with low light scattering properties [62,63].…”

Section: Contrast Ratiomentioning

confidence: 99%

Technical evolution of liquid crystal displays

2009

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I n 1888, more than a century ago, the Austrian botanist FriedrichReinitzer discovered an intermediate state of matter between isotropic liquid and lattice-structured crystal [1][2][3]. Th is state, later termed liquid crystal (LC), remained merely a novelty for many years until suitable applications for the technology began to become apparent. From the late 1960s, following the realization that various display applications were possible, the popularity of liquid crystal as a research fi eld expanded rapidly, attracting the interest of many scientists who made fundamental contributions to the technologies that have led to the spectacular success of liquid crystal displays (LCDs) [3][4][5][6][7][8][9][10][11][12][13]. Th e development of the twisted nematic (TN) [4] and supertwisted nematic (STN) [5] cell confi gurations, along with the necessary manufacturing technologies [6][7][8][9], resulted in the birth of the LCD industry in the late 1970s and early 1980s. The subsequent development of thin-film transistor (TFT) technology provided a further boost to the industry in the late 1980s [14,15]. Th e boom was signifi cantly supported by the advancement of material technologies such as the highly reliable manufacturing of liquid crystal base materials, and the development of polymers for the alignment layer, color fi lter materials, and sheet-type polarizers formed from the poly(vinyl alcohol)-iodine complex.In the 1990s, LCDs occupied an important position in the display market primarily through notebook applications, although the cathode ray tube (CRT) continued to dominate the desktop monitor and television markets. Th e plasma display panel (PDP), which appeared in the commercial market in 1997, pioneered the large-area fl at panel display market. It was widely predicted at the time that PDPs would maintain the lead in the large-area display market and that LCDs in small-display information technology (IT) applications would soon be replaced by new technologies such as displays based on organic light-emitting diodes (OLEDs) [16,17]. Such predictions were based on the belief that the LCD technology suff ered from serious limitations in terms of both off -axis image quality and moving picture quality, and also that it had proved diffi cult to obtain reasonable manufacturing yields of large-area TFT panels. However, these predictions, as we now know, turned out to be incorrect. Th e application of LCDs has expanded rapidly in recent years from purely information technology (IT) applications to the television and mobile display markets, and now even to very-large-area digital information displays (DIDs).Interestingly, while LCDs penetrated the traditional territories of other display technologies including CRTs and PDPs, attracting inevitable and heavy competition from these technologies, the most critical competitors were in fact alternative LCD technologies. A range of LCD modes and technologies are now applied in the same areas of application and are compared directly with one another in the market. In applicat...

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“…Especially, IPS mode is intensively take center stage due to wide viewing angle, fast response time and its low distortion against external force as interactive display panel increase. However, in case of IPS mode, contrast ratio at normal direction is relatively low and thus many kinds of approaches have been attempted in terms of internal and external improvement [4]. Even though contrast ratio improvement in IPS panels can enhance a contrast ratio, it is still shortage to obtain a sufficient black level required in high dynamic range (HDR) technology.…”

Section: Introductionmentioning

confidence: 99%