King-Lien Lee

Effect of Micro-Structural Light Guide Plate on Source of Linearly Polarized Light

In this work, three micro-structural plates are designed to guide linearly polarized light that is assumed to be emitted from four light emitting diodes in a typical compact liquid crystal display device. The brightness and uniformity of the emission from each guide plate are simulated for various orientations of linear polarized light. The experimental results show that the new light guide plate with two differently micro-structural v-cut surfaces provides higher brightness and uniformity of the output light.

Director Model for the Electro-Optics of Blue-Phase Liquid Crystal

We propose a theoretical model to explain the electro-optical properties of a blue-phase liquid-crystal (BPLC) cell. This is the first time that a BPLC cell can be simulated using a simple model. Instead of employing the Kerr effect, we model the BPLC cell using a series of nematic liquid-crystal layers, and study the behavior of the liquid-crystal director. With the help of this model, the electro-optical properties and the response time can be calculated by a commercial simulator, and the calculated results are in good agreement with the experimental data.

Simulation of the in-plane-switching blue-phase liquid crystal using the director model.

We analyze the non-uniform electric field distribution in an in-plane-switching blue phase liquid crystal (IPS-BPLC) cell and use the director model to simulate the electro-optical properties of an IPS-BPLC cell using a commercial simulator. The calculated results are in good agreement with the experimental data.

Brightness Enhancement with a Fingerprint Chiral Nematic Liquid Crystal

We demonstrate a brightness enhancement element that can be laminated to a linear polarizer for increasing the optical efficiency of a liquid crystal display device. The device structure is a chiral nematic liquid crystal (CNLC) with a fingerprint texture. For an unpolarized incident light, our experimental results show that the combination of a CNLC film and a conventional linear polarizer can achieve a transmittance of over 50%. The CNLC film increases the optical efficiency of a conventional polarizer by 21.7%. The detailed mechanism of such a CNLC-polarizer system is analyzed.

Study of Twisted Optically Compensated Bend Cell Using Patterned Alignment

We have investigated a new liquid crystal cell based on a nonchiral-doped optically compensated bend (OCB) mode. The average pretilt angle of this cell was higher than that of a conventional OCB cell; when undisturbed, the twist-to-splay energy barrier induced by topological differences remained in a twist state. We have called this twisted cell a twisted optically compensated bend (TOCB) cell. The TOCB cell does not require any warm-up time or warm-up voltage in electrical driving, and the response time of the TOCB cell was as fast as that of a conventional OCB cell. In this study, the TOCB cell was made using a polymer network pattern with high-pretilt-angle alignment, called a patterned-TOCB cell. The patterned-TOCB cell arose from the irradiation of UV light through a photomask and onto a pi cell, which was filled with nematic liquid crystal (NLC) and UV-curable polymer mixture upon a curing voltage being applied to it.

Electro Optical Characteristics of High-Pretilt Twisted Liquid Crystal pi-Cells

We studied the transformation between the twist state and bend state of a twist-stabilized optical compensated bend (TOCB) nematic liquid crystal cell. The theoretical calculation results show that when driving the TOCB cell, the bend-to-twist transition results in an optical bounce in the optical transmittance. To eliminate the optical bounce, the substrate pretilt angle should be larger than a critical value (26°). The TOCB cell with a critical pretilt angle of about 26° does not require a warm-up voltage, but achieves high transmittance, fast response, and a wide viewing angle.

Design of directional light source for blue phase LCD

We propose a light guide plate of an oblique incident light source for a vertical- field-switching blue phase liquid crystal display. The LGP consists of a designed microstructure bottom surface and other specially microstructure top surface. We simulated the LGP of a backlight system by optical software (TraceProTM) and the performance of the BPLCD by liquid crystal software (TechWiz). The result shows that the output rays mainly emit at 59° and the uniformity is 78.84%. The designed applicable light guide plate successfully increase the angles of oblique light source and provide a better uniformity of illumination for a vertical-field-switching blue phase liquid crystal display.

Knowledge asset-based three-stage model of innovative enterprises evolution

Innovative enterprises achieve sustainable competitive advantages by means of innovation instead of anything else. During this process, knowledge assets and the value-adding activities related always play a fundamental role which changes in accordance with the evolution of sustainable competitive advantages and results in the evolution of different business models of innovative enterprises. Based on the analysis of these correlative changes, the knowledge-based three-stage model of innovative enterprises evolution is proposed. Basically, it illustrates the development of innovative enterprises from technology management, to innovation management, and to intellectual property operation. At each stage, the types of knowledge assets and core value-adding activities are summarized and the according business model of innovative enterprises is suggested respectively. The hypotheses are further testified with a case study of Baosteel Group Corporation in China and the policies for incubating innovative enterprises are suggested thereafter.