Liquid Crystals for Superior Electro‐Optic Performance Display Device with Power‐Saving Mode

Abstract

for the additional power reduction in the liquid crystal driving scheme, for example, by reducing the driving frequency f. Displaying smooth and dynamic motion at high-frame rate has been an unquestionable direction to improve the performance of displays, but static images are also becoming significantly important as the application of displays diverges. Thus, as the f is in linear dependence on the power consumption of a module, low-f driving LCD is desired.In driving scheme of LCDs, some amount of electromagnetic radiant energy from the backlight is cut off by the combination of crossed polarizers and liquid crystalline medium while modulating polarization. In terms of energy loss in a liquid crystal layer, therefore, maximizing transmittance is an important factor to improve for better electro-optic performance. From this perspective, achieving both high optical transmittance and low-f driving would be a remarkable breakthrough in terms of power savings.There are two main streams of the initially homogeneous aligned light modulating mode in LCDs: fringe-field switching (FFS) and in-plane switching (IPS) modes. Both modes have a patterned electrode on the one side of two sandwiched substrates. In the IPS mode, patterned pixel (signal-swung) and common electrodes are interdigitated such that symmetrical lateral fields, which have the same translational periodicity with the electrode patterns, are formed between these two electrodes to rotating the liquid crystal director in plane; thus, reorientation occurs only in between the electrodes. In the FFS mode, on the other hand, a plain common electrode and a patterned pixel electrode are not on the same layer and separated by an insulation layer. With this structure, the electric fields form nonsymmetrical fringe shape and the field periodicity is half of the pitch of the electrode patterns. Thus, the rotation of the liquid crystal director takes place over the entire electrode area, which contributes more to the optical transmittance. [4,5] The FFS mode has been dominating the LCD market, especially in portable devices owing to the high aperture ratio, high transmittance, low operation voltage, wide-viewing angle, and touchscreen tolerance. [4,6] Consequently, intensive efforts to reduce the power consumption of this mode have been attempted by using the low-f driving when static images are being displayed. However, severe issues regarding image quality arise in the low-f driving, including image-flickering owing to flexoelectric effect. [7][8][9][10][11][12][13][14] The flexoelectric effect is a An advantageous factor for the technology of displays is low power consumption. For power-saving, low-frequency driving of liquid crystal displays (LCDs) is useful. However, an unacceptable performance drop, from image-flickering, occurs due to occurrence of the flexoelectric effect. Here, based on close agreement between experimental and simulated results, a new electro-optic mode with optimization of both electrode structures and physical properties of the liquid crystal...

Flicker‐Free Fringe‐Field Switching Liquid Crystal Display Operable at Extremely Low Frequencies for Power Saving

“…[ 1–4 ] Achieving an effective pixel aperture ratio related to the light transmittance level is important in reducing the power consumption of LC display (LCD) panels, which would resolve the battery capacity limit of portable devices. [ 5,6 ] Recently, additional efforts have been devoted to improving power saving by adopting local dimming techniques in backlight units or by improving the operation scheme in logic parts. [ 7–10 ] In LCDs operated by alternating current (AC) signal voltages to avoid charge‐induced image flickering, the power consumption by the operation circuits can be expressed as follows [ 10 ] where P l , f d , C , and V d represent the logic power consumption, driving frequency, load capacitance, and driving voltage of the LCD panel, respectively.…”

Photocontrollable Resistivity Change in Nanoparticle-Doped Liquid Crystal Alignment Layer: Voltage Holding and Discharging Properties of Fringe-Field Switching Liquid Crystal Modes

“…However, with increasing pixel density, the mobile display panels suffer from power consumption issues. Because the power consumption level in driving circuits is proportional to the operation frequency [6,7], extensive efforts have been made to reduce the operation frequency level of FFS LC modes without degrading the image quality [8][9][10][11][12][13][14][15][16].…”

38‐5: Student Paper: Waveguide Liquid Crystal Display with Light Waveguide Plate for Transparent Display

“…In the growing demands, various types of display techniques have developed for transparent displays, including the conventional liquid crystal display (LCD) [7], such as twisted nematic (TN) [8], in-plane switching (IPS) [9], vertical alignment (VA) [10], and fringe field switch (FFS) [11], Organic light emitting display (OLED) [12], polymer dispersed liquid crystal (PDLC) display [13], polymer network liquid crystal (PNLC) display [14], electrochromic display (EC) [15], and micro light emitting display (Micro-LED) [16], et al An emerging promising display technology for transparent display is the light waveguide LCD which, besides the excellent features of LCDs, such as high resolution, low manufacturing cost and light weight, has the new merits of high light efficiency and high transmittance of voltage-off state. The light waveguide LCD consists of two parallel glass substrates with a polymer stabilized LC sandwiched between them.…”