Planar lightwave integrated circuits with embedded actives for board and substrate level optical signal distribution

This paper explores design options for planar optical interconnections integrated onto boards, discusses fabrication options for both beam turning and embedded interconnections to optoelectronic devices, describes integration processes for creating embedded planar optical interconnections, and discusses measurement results for a number of integration schemes that have been demonstrated by the authors. In the area of optical interconnections with beams coupled to and from the board, the topics covered include integrated metal-coated polymer mirrors and volume holographic gratings for optical beam turning perpendicular to the board. Optical interconnections that utilize active thin film (approximately 1-5 /spl mu/m thick) optoelectronic components embedded in the board are also discussed, using both Si and high temperature FR-4 substrates. Both direct and evanescent coupling of optical signals into and out of the waveguide are discussed using embedded optical lasers and photodetectors.     

Analysis of brushless three-phase synchronous generator without exciter

Recently, a demand for small-capacity generators has been increasing as electric sources in small ships and automobiles or as portable electric sources driven by engines. It is desired that the structure of small-capacity generators be simple and robust, and that the generators be highly reliable, easily maintained and controlled. This paper describes an analysis of the original brushless synchronous generator without exciter. The output voltage can be adjusted in the wide range by controlling the stator dc current. To analyze the characteristics of this generator, the finite element method is applied. It is found that the results of theoretical analysis agree well with the experimental results.     

Longitudinal elastic waves in columns due to earthquake motion

An analysis is presented of longitudinal waves in a thin elastic column. Velocity is specified at one end, and the boundary condition at the other end is expressed in terms of a range of effective impedances of an attached structure. Propagation, reflection and interference of the waves are followed by the method of characteristics. Integration of differential equations along characteristics yields the wave-induced stress, which is then applied to problems of earthquake excitation. Numerical examples are given for recorded updown ground motion of the Kobe Earthquake.     

Simultaneous measurement of the resistivity and permeability of afilm sample with a double coil

A method is proposed for a simultaneous measurement of the resistivity and permeability of a film inserted between two coils facing each other. Connecting in series, the total impedance of the coils was measured in two ways, i.e., 1) the current passes through the coils in the same direction, and 2) the current passes through each coil in opposite directions to each other. The resistivity and permeability of the film were simultaneously obtained from the difference in the impedance for the two cases. It was theoretically found that the optimum frequency for high accuracy in the measurement was proportional to the resistivity and inversely proportional to a thickness of a sample film. The results of the simultaneous measurements of the resistivity and permeability of nickel films of a thickness ranging from 0.01-0.08 mm at a frequency range of 1-100 kHz are shown in this paper. The measured values of the resistivity and permeability with this method agreed with the values obtained by conventional methods, i.e., the dc four-probe method for the resistivity measurement and the toroidal coil method for the permeability measurement     

Wide gamut LCD using locally dimmable four‐primary‐color LED backlight

This paper proposes a wide gamut LCD using locally dimmable four‐primary‐color (4PC) LED backlight. Although the color gamut of LCDs has been improved in recent years, it is insufficient to reproduce all the colors in the real world. The objective of this paper is to propose a wide gamut LCD that reproduces all the colors in the real world while keeping the cost increases to a minimum. We evaluated the color gamut reproduced by LEDs of multiple primary colors and selected cyan as the optimal color to be added to the three primary colors to reproduce all the colors in the real world. Therefore, we designed an LED backlight consisting of an additional only‐cyan LED with three‐primary‐color LEDs and developed a prototype LCD with 4PC LED backlight. Furthermore, we developed a local dimming algorithm for the 4PC LED backlight. As a result, we confirmed that the prototype LCD with the 4PC LED backlight is able to cover almost all the colors in the real world and also able to display natural images with highly saturated colors by local dimming.     

Principle and operation of a new type motor consisting of piezoelectric device and strain wave gearing

The authors have developed a new type of motor consisting of a piezoelectric device and strain wave gearing, and is called a piezoelectric motor. This is a first step in realizing a low-speed, small-size and lightweight motor. The principle of the motor is that the traveling wave is produced by piezoelectric devices and displacement conversion devices without mechanical resonance, and the torque to rotate the motor is generated by a mechanism of strain wave gearing (circular spline and flexspline) without using friction. The motor is operated at variable frequency and its rotational position (angle) is controlled in open-loop because it is basically a synchronous motor. In this paper, the structure and principle of the proposed motor are explained and the driving method and the mechanical characteristics of an experimental motor also are described. The results are as follows:

• 1 The realizability of the proposed piezoelectric motor is verified experimentally. The experimental motor operates at 2920 steps per revolution, and its speed range is 0 to 960 pps [or 0 to 20 (rpms)].
• 2 The torque characteristics are clarified qualitatively.
• 3 The generated torque of the experimental motor is small (less than 0.03 Nm) and therefore the improvement of the torque is an important subject hereafter.
• 4 It is possible to construct the motor with nonmetallic material. This fact is considered to facilitate obtaining a means to lighten the weight of the motor in the future.

     

Phase Formation and Microstructure of Titanium Oxides and Composites Produced by Thermal Plasma Oxidation of Titanium Carbide

The phase formation and microstructure of titanium oxides and composites produced by Ar–O₂ thermal plasma oxidation of titanium carbide powders were investigated in detail by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Relationships between the phase compositions and microstructures of the oxides were established by combined structural and phase analyses, in correlation with synthesis conditions and phase formation mechanisms. It is revealed that vapor condensation favored the formation of anatase, which existed as smaller particles, while liquid/solid oxidation favored the formation of rutile, which appeared as larger particles or composites. A higher oxygen input in the plasma gases (Ar + O₂) enhanced the formation of anatase due to impeded oxidation and evaporation. A small amount of Ti₄O₇ and Ti₃O₅ was detected in the larger particles coexisting with rutile or TiC. These suboxides were formed as intermediates in solid oxidation of TiC or precipitated from the Ti–C–O melt during cooling. Furthermore, extensive cracks, dislocations and stresses were observed in the monolithic rutile and composites, in association with the rapid quenching in this high-temperature in-flight oxidation process.     

Note: detection of micro-cracks in the interlayer dielectric film by the stress based light scattering method

A phenomenon was discovered wherein light scattering strength from cracks increases when tensile stress is applied to micro-cracks produced in the interlayer dielectric film by chemical mechanical polishing treatment. It is likely that the change in light scattering intensity occurs because a region of high stress concentration (region with high variation in index of refraction) is produced near the crack tip due to stress, thus forming a type of scatterer. With this method, it is possible to detect only scatterers which respond to stress, and thus, it is possible to classify and separately detect cracks and particles.