Surface-controlled patterned vertical alignment mode with reactive mesogen

We present a polarization-dependent prism array film for controlling the viewing angle distribution of liquid crystal (LC) display panels without loss of light efficiency. On a directional backlight unit, our polarization-dependent prism array film, made into a stacked bilayer with a well-aligned liquid crystalline reactive mesogen (RM) layer on the UV-imprinted prism structure, can continuously control the light refraction function of the prism array by electrically switching incident polarization states of a polarization-controlling layer prepared by a twisted nematic LC mode. The viewing angle control properties of the polarization-dependent prism array film are analyzed under different prism angle and refractive index conditions of the RM layer. A simple analytic model is also presented to describe the intermediate viewing angle distributions with continuously varying applied voltages and incident polarization states.

Section: Introductionmentioning

confidence: 99%

Continuous Viewing Angle Distribution Control of Liquid Crystal Displays Using Polarization-Dependent Prism Array Film Stacked on Directional Backlight Unit

Park

Joo

et al. 2016

“…In this case, the pretilt is produced from the fixation of surface LCs due to the solidification of RM huddled on the surface by UV exposure under a proper electric field, which provides some tilt to the surface LCs. In addition, Lee et al presented the surface controlled patterned vertical alignment (SC-PVA) mode using a reactive mesogen (RM)-doped polyimide-mixture to produce a proper pretilt of LCs in pixels instead of a LC mixture [19]. The pretilt and azimuthal angles were memorized on the LC alignment layer with the polymerization of a doped RM monomer through UV exposure under a proper electric field.…”

Section: Introductionmentioning

confidence: 99%

Advanced Patterned Vertical Aligned Nematic Mode to Elevate Transmittance

Gwag¹

2014

Self Cite

This paper presents an advanced patterned vertical aligned nematic liquid crystal (APVA) mode as a way of improving the transmittance of the conventional patterned, vertically-aligned nematic liquid crystal (PVA) mode. The APVA was characterized by multi-electrodes, which play an important role in generating a horizontal electric field that prevents LC disclination in the vicinity of the middle region of electrodes between top and bottom slits in PVA mode. The proposed APVA mode focused on improving dramatically the transmittance with excellent image quality. In the simulation, the APVA mode improved the transmittance by more than 22%, compared to the conventional VA modes. Therefore, it is useful to upgrade the LCD display quality.

“…However, the response time of the VA mode is not sufficiently fast to realize high-quality video [11,12]. To reduce the response time several methods have been proposed [13][14][15][16][17][18][19][20][21][22][23][24], but they have drawbacks, such as a complicated driving scheme, complex fabrication process, and increase in the operating voltage. Moreover, there have been only a few studies of the fast switching of LCs at low temperature.…”

Section: Introductionmentioning

confidence: 99%

Fast Switching of Vertically Aligned Liquid Crystals by Low-Temperature Curing of the Polymer Structure

Park¹,

Oh²,

Kim³

et al. 2014

We proposed a method for fast turn-off switching of a vertically-aligned liquid crystal cell by low-temperature curing of the polymer structure. We confirmed that the turn-off times of the fabricated cells were reduced significantly as the curing temperature was lowered to -20℃. We accounted for the effect of low-temperature curing on the turn-off time by using a mathematical model and by observing images obtained via scanning electron microscopy. We also confirmed that low-temperature curing is more effective in reducing the response time when the device is operated at a low temperature.