High-transmittance polymer-stabilised blue-phase liquid crystal display with double-sided protrusion electrodes

Abstract

A polymer-stabilised blue-phase liquid crystal display (PSBP-LCD) with double-sided protrusion (DSP) electrodes structure is proposed. The oblique electric field between the protrusion electrodes inside both top and bottom glass substrates can induce more isotropic-to-anisotropic transition in the polymer-stabilised blue-phase liquid crystal (PS-BPLC) medium through Kerr effect than using the in-plane switching electrode. For the same electrode width, spacing and cell gap, the transmittance of PSBP-LCD with the DSP electrodes is ∼29% higher than that using the IPS electrode. IntroductionPolymer-stabilised blue-phase liquid crystal display (PSBP-LCD) based on the Kerr effect [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] has the potential to be the next-generation display technology due to the following reasons: (1) its sub-millisecond gray-to-gray response time, [1,2] which is ten times faster than the present nematic LC displays; (2) it does not need alignment layer so that the fabrication process is greatly simplified; (3) it has a wide viewing angle -the voltage-off state is optically isotropic and the voltage-on state forms multi-domain structures [3,4] and (4) the transmittance is insensitive to the cell gap, so it can be used in large-screen LCDs. However, there are still many problems to be overcome, such as high operating voltage, low transmittance, large hysteresis and long-term stability.Recently, several approaches have been proposed to lower the operation voltage. [5-9] For instance, a polymer-stabilised blue-phase liquid crystal (PS-BPLC) material with a large Kerr constant (K∼12.68 nm/V 2 at λ = 550 nm) [10-13] has been recently developed. By optimising the in-plane switching (IPS) electrode width and gap, the driving voltage is reduced to ∼35 V. and protrusion electrodes [15] show very positive trend to lower the operating voltage to ∼10 V using PS-BPLC material with a large Kerr constant (12.68 nm/V 2 at λ = 550 nm), but the fabrication is complicated and the transmittance is greatly lowered. An enhanced protrusion electrode structure was proposed to enlarge the transmittance.[16] The dead zones are eliminated by the IPS-like structure on the top of the protrusions,

Polymer‐stabilized blue phases: promising mesophases for a new generation of liquid crystal displays

“…One of the major challenges is reducing the voltage V m [100][101][102][103][104][105][106][107] below 10 V, thereby enabling electric addressing with thin film transistors. In addition, it is important to lower the hysteresis ΔV [108][109][110][111][112][113][114][115][116][117][118][119][120][121] in order to achieve reproducible gray levels. A large optical contrast between the bright and the dark state is only possible if no non-zero intensity I 0,2 caused by residual birefringence [122] appears after removing the voltage.…”

Enhancement of birefringence of liquid crystals with dispersion of poly (n-butyl methacrylate) (PBMA)

“…These interactions depend upon the nature of polymeric chain, the properties of the LC medium and LC ordering on the surface of polymeric layer. Very recently, modified LC materials have been applied [9][10][11] in display industry for achieving better performance of devices. Su et al [9] have shown that the transmittance of the polymer-stabilised blue-phase liquid crystal display with double-sided protrusion is 29% higher than that using the IPS electrodes.…”

“…Very recently, modified LC materials have been applied [9][10][11] in display industry for achieving better performance of devices. Su et al [9] have shown that the transmittance of the polymer-stabilised blue-phase liquid crystal display with double-sided protrusion is 29% higher than that using the IPS electrodes. Zhang et al [10] observed unique optical features in a cholesteric liquid crystal with helically aligned molecules.…”

Blue phase dual‐view liquid crystal display based on directional backlight system

“…The electrode shapes, cell gaps ( d ), electrode widths ( w ), and electrode gaps ( l ) will affect the transmittance of LSP and RSP. In our simulation, we adopt the protrusion electrode . The electrode width w = 5 μ m, the electrode gap l = 3 μ m, and the cell gap d = 3 μ m. And the taper angle is 30 °, which means the height of protrusion electrode is h = 1.4 μ m. This patterned electrode structure has the feature of high transmittance and low light leakage.…”

“…In our simulation, we adopt the protrusion electrode. 13,14 The electrode width w = 5 μm, the electrode gap l = 3 μm, and the cell gap d = 3 μm. And the taper angle is 30°, which means the height of protrusion electrode is h = 1.4 μm.…”