FMBA(Fast Moving Ball Actuator), developed as novel electronic-paper display, has already proven its operability and functionality. However, optimization issues related with low operating voltage, high refresh rate, fine pixel and higher display resolution, etc. are still remaining to be improved for a successful commercialization. In order to optimize such issues effectively, static and transient model were developed and verified by comparing the calculated results to the measured. The static model is based on the force balancing equation between the driving and the holding forces while the transient model is developed from Newton’s 2nd law by adding the inertia as well as the resistive damping forces caused by the surroundings. With the simplified static model, driving voltage of 30.71 V was obtained, which is reasonably matched to the measured voltage of 40 V. Based on the transient model, also, the transient response of the device can be estimated within reasonable margin. Considering the absence of reliable key parameters of surface roughness, static and dynamic frictional coefficient, and refractive indices, the developed static and transient models account well the experimental results and thus they are expected to contribute further improvements in FMBA.
We present a thermal property estimation method required for a bolometer design and demonstrate the utilization of a
presented method to the scaled μ-bolometers. The estimated thermal properties of 25μm pitch VOx bolometers with our
presented method shows K=1.33x10<sup>-8</sup> W/K, H=1.36x10<sup>-10</sup> J/K, τ<sub>th</sub>=10.2 ms for an active bolometer and K=1.64x10<sup>-6</sup>
W/K, H=1.82x10<sup>-10</sup> J/K, τ<sub>th</sub>=111 μs for a reference bolometer. These estimated thermal properties have a good agreement
with the previous reports and with results from the FEM analyses carried on the same bolometer designs. The presented
method is useful to estimate thermal properties of a scaled bolometer and to estimate thermal properties of a specific
The common feature of bistable liquid crystal displays (LCDs) is the existence of the two stable states without an
external field. In the bistable chiral splay nematic (BCSN) mode, the splay and π twist states are used for the two stable
states. The BCSN mode is a potential candidate of bistable modes, because it can be operated not only as a storage
device, but also as a monostable device with a fast response time in the same panel. The transition between two memory
states of the BCSN LCD is strongly coupled with the strength of applied electric fields. In this paper, we investigated the
bistable property by calculating the bistable curves and the correlation between the horizontal electric fields strength. To
realize the gray scale of BCSN LCD, We also propose a grid electrode structure with the varying-space between
electrodes which causes the varying strength of the horizontal electric fields. The selective transitions by the electrode
structure are demonstrated in this paper.
In this paper, the performance enhancing method by increasing optical fill factor of a μ-bolometer is proposed. The main
idea of increasing optical fill factor of a μ-bolometer is the reducing the leg area without deteriorating the thermal and
electrical properties of its legs. We propose 'the self align leg' structure in order to reduce the leg area without
deteriorating electrical and thermal properties. From the analysis, this method can give some benefits, the improvement
of responsivity up to 9% and noise equivalent temperature difference 13% through fill factor increasing by 5 to 7%. A
new plausible method of increasing fill factor can easily be incorporated with a conventional process without
considerable change of process.
The capsule endoscope, a new application area of digital imaging, is growing rapidly but needs the versatile imaging
capabilities such as auto-focusing and zoom-in to be an active diagnostic tool. The liquid lens based on MEMS
technology can be a strong candidate because it is able to be small enough. In this paper, a cylinder-type liquid lens was
designed based on Young-Lippmann model and then fabricated with MEMS technology combining the silicon thin-film
process and the wafer bonding process. The focal length of the lens module including the fabricated liquid lens was
changed reproducibly as a function of the applied voltage. With the change of 30V in the applied bias, the focal length of
the constructed lens module could be tuned in the range of about 42cm. The fabricated liquid lens was also proven to be
small enough to be adopted in the capsule endoscope, which means the liquid lens can be utilized for the imaging
capability improvement of the capsule endoscope.