Cell Gap-Dependent Transmittance Characteristic in a Fringe Field-Driven Homogeneously Aligned Liquid Crystal Cell with Positive Dielectric Anisotropy

Abstract

The photoluminescence of porous silicon prepared by etching in an aqueous solution of hydrofluoric acid mixed with phosphoric and that with nitric acid were red and orange, respectively. The optical characteristics were stable under laser illumination or when stored in air for the aging test. For etching in an aqueous hydrofluoric acid/phosphoric acid electrolyte, the stability is attributed to the existence of Si-P and P-O-Si bonds formed on the porous silicon surface. For etching in an aqueous hydrofluoric acid/nitric acid electrolyte, it is attributed to more Si-O bonds formed on the porous silicon surface.

Role of the elastic constants of a liquid crystal with positive dielectric anisotropy in the electro-optic characteristics of fringe-field switching mode

“…Consequently, the twisted angle above the centres of the pixel and common electrodes is less in the +LC than in the -LC, giving rise to lower transmittance in the +LC than in the -LC in those positions. [18] As a result, the transmittance is more strongly dependent on electrode positions in the +LC than in the -LC. Therefore, if one can suppress tilt angle at positions B and D, higher elastic torques on LC at position C will be given, generating higher rotation angle and consequently higher transmittance.…”

“…Then, -LC in the FFS LCDs becomes an alternative for compensating the loss of the transmittance in such a high-resolution display and thus it starts to be commercialised again, although the response time and operating voltage are not satisfactory. Electro-optic studies on the FFS mode with +LC have already been performed extensively and it was known that the transmittance of the FFS LCDs depends on many cell parameters such as electrode structure, [7,[11][12][13] rubbing direction, [14] retardation value of the LC layer, [15,16] cell gap, [17,18] and sign and magnitude of dielectric anisotropy (Δε). [19][20][21][22] To improve the performance of the FFS mode and make it more efficient, one needs to know the dependence of switching behaviour on the intrinsic physical properties of the LC material.…”

Electro-optic Characteristics of the Fringe-Field Switching Liquid Crystal Mode, Status of Applications, and Future Issues (Invited Paper)

“…초기 수평배열된 액정층의 전압 인가에 따른 액정 층 위치에 따라 꼬임 정도는 인가된 전기 에너지와 액정 셀의 탄성에너지의 경쟁으로 결정된다. [19][20][21] . 즉 전극 위치 A에서는 액정 방 향자 분포가 IPS모드와 유사하고 전극 위치 C에서는 TN모 드와 유사하다.…”

“…하지만 B지점에서 서 있는 정도가 덜한 -LC의 경우 이 의존성은 약하다. FFS모드 에서 투과율은 셀갭이 4㎛에서 3㎛로 감소시 투과율이 감소 하게 되는데 이는 역시 셀갭이 감소시 탄성토크에 의한 A지 점의 투과율 감소 영향과 더불어 전극 위치에 따른 투과율을 극대화는 전압이 다르기 때문이다 [28,29] . 이러한 단점은 가능 한 전극폭을 약 2㎛로 줄이고 간격을 3~4㎛정도 가져가면 탄성토크 영역이 최소화하며 투과율이 극대화된다 [18,30,31] .…”

P.103: High Transmittance LC Mode Based on Fringe Field Switching of Vertically‐Aligned Negative LCs

“…LCDs for these applications require high display performances, such as a high contrast ratio, wide viewing angle, fast response, and high transmittance. In particular, high transmittance is required because the aperture ratio can be reduced as the pixel size decreases for ultrahigh resolution [1,2].Several LC modes including in-plane switching (IPS) [3][4][5], fringe-field switching (FFS) [6][7][8], and vertical alignment (VA) [9,10] modes have been in competition with each other in the LCD market [11,12]. Among these modes, the IPS and FFS modes provide wide viewing angle.…”