• Journal of Information Display
• /
• v.12 no.2
• /
• pp.97-99
• /
• 2011

We report flexible, bistable cholesteric displays utilizing polyester (PET) substrates with printed internal black electrodes. The black electrodes consist of carbon ink dispersed in butyl carbitol using a patented roll-to-roll gravure-offset printing. A transparent conducting polymer printed on PET serves as the counter electrode. The electro-optic material is a chiral nematic mixture dispersed in a low-concentration polymer binder. The device can be switched between scattering (black) and reflective (vibrant green) states upon application of an electric pulse. The internal black electrode enhances the contrast of the display and simplifies the roll-to-roll manufacture of flexible displays.

• Journal of Information Display
• /
• v.4 no.1
• /
• pp.1-8
• /
• 2003

Recent progress in both low pretilt and high pretilt defect free C1 surface stabilized ferroelectric liquid crystal (SSFLC) devices is reviewed. First, by numerical calculation to investigate the balance between surface azimuthal anchoring energy and bulk elastic energy within the confined chevron layer geometry of C1 and C2, it is possible to achieve a zigzag free C1 state by low azimuthal anchoring alignment with a low pretilt angle. The critical azimuthal anchoring coefficient for defect free C1 state is calculated. Its relationship with elastic constant, chevron angle as well as surface topography effect are also discussed. Second, using $5^{\circ}$ oblique SiO deposition alignment method a defect free, large memory angle, high contrast ratio and bistable C1 SSFLC display, which has potential for electronic paper applications has also been developed. The electrooptical properties and bistability of this device have been investigated. Various aspects of defect control are also discussed.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2009.10a
• /
• pp.625-628
• /
• 2009

In the bistable chiral splay nematic (BCSN) mode, the splay and ${\pi}$ twist states are used for the two stable states. The switching property is strongly dependent on the amplitude of the electric field. In this paper, we investigated the gray scale capability of BCSN liquid crystal display (LCD) by the gradual horizontal electric field caused the interdigital electrode of by the inequality gap. We demonstrate the gray scale of the BCSN LCD during transition process under the horizontal electric field.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2009.10a
• /
• pp.502-504
• /
• 2009

We demonstrate a pixel-isolated bistable twist-splay namatic (PI-BTSN) liquid crystal (LC) cell which has two stable states of splay and ${\pi}$-twist. Each state is stabilized by a multi-dimensional anchoring effect of pixel-isolating polymer walls without any chiral additives. Polymer walls are formed around the pixel region by anisotropic phase separation between LCs and reactive mesogens. Switching between the two states is archived by using vertical and horizontal electric fields. The memory mode of the fabricated LC cell has shown infinity memory time.

• Journal of Information Display
• /
• v.12 no.2
• /
• pp.101-107
• /
• 2011

To come up with a bistable liquid crystal (LC) device using unpolarized UV light, single-step laser patterning on a photoalignment layer using a photomask was proposed to achieve an equilibrium configuration of LC molecules in contact with a periodically patterned substrate. The patterns were formed by stripes of alternating random planar and homeotropic anchoring on a submicrometer scale in the order of $0.5{\mu}m$. Two possible configurations of bistable LC cells that can be obtained by combining a micropatterned surface formed with alternating random-planar- and homeotropic-alignment with planar- or homeotropic-alignment surfaces were proposed. The alignment properties of the two proposed models were investigated, along with the microscopic switching behavior of micropatterned nematic LC cells.

• Korean Journal of Optics and Photonics
• /
• v.19 no.3
• /
• pp.161-168
• /
• 2008

We propose a novel bistable nematic liquid crystal cell, which has a dual-frequency liquid crystal material and pixel-isolating polymer wall formed by an anisotropic phase separation of a mixture of liquid crystals and UV-curable pre-polymers. The proposed cell has two stable states of left- and right-handed ${\pi}$-twist. The switching between the two states is achieved by using a sequential waveform of low and high frequencies. A transmissive bistable liquid crystal display is designed, which achieves high contrast ratio by using the proposed cell and optical films.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2007.08a
• /
• pp.538-541
• /
• 2007

In this paper, with a bistable curve of the bistable chiral splay nematic liquid crystal (BCSN LC) device, we clarify how the twist-to-splay transition is achieved under a horizontal field. By a sufficiently high horizontal electric field, the bistable property becomes monostable. The transition can be achieved.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2007.08a
• /
• pp.982-985
• /
• 2007

The authors report methods of fabrication singlelayer color cholesteric liquid crystal displays (CLCDs). A single-layer CLCD has been prepared from a polymerstabilized cholesteric liquid crystal. The unique feature of the polymer stabilization is in that the electrically switched colors preserve high reflectivity. A bistable single-layer CLCD has been prepared by the formation of polymer barrier walls and light-tuned cholesteric pitches to reflect blue, green and red color sub-pixels.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2005.07a
• /
• pp.187-190
• /
• 2005

Alignment pattern of checkerboard was constructed by the stylus of atomic force microscope. Orientational bistability of the nematic liquid crystal was realized on that frustrated surface alignment. Macroscopic orientational switching between two perpendicular directions took place by an appropriate in-plane electric field. The threshold electric fields decreased in both switching directions as temperature increased. The focused laser heated up only the limited domains in the cell including a light-absorbing medium. Irradiating the laser concurrently with an appropriate electric field, we switched the selected unit domains in the alignment pattern. The switched domains maintained stably the switched direction without the disturbance from the exterior. Extending and repeating this process, we realized extremely fine devices of bistable switching.

• Journal of Information Display
• /
• v.6 no.3
• /
• pp.1-5
• /
• 2005

The recent Bistable Nematic ($BiNem^{(R)}$) LCD technology presents long term bistability, high level passive matrix multiplexing, gray levels capabilities and high optical quality. The $BiNem^{(R)}$ device, based on anchoring breaking, needs specific low anchoring strength materials - alignment layers and liquid crystal mixtures. We present here our approach to develop nematic mixtures with wide enough temperature range and low zenithal anchoring energy.