Research and Development
Technical Report

1.Luminance and Luminous Efficiency Observed above the Anode Electrode in a Co-Planar Structured AC-PDP

Summary

As a result of improving the luminous efficiency in Plasma Display Panels (PDPs),the emission state or distributions in a co-planar structured AC-PDP were investigated as a function of time and position of the electrodes with respect to phosphor-visible light, Xe-infrared light and Ne-visible-red light using a Streak Camera.
It has been believed that the emission of PDPs takes place at the cathode site alone. However our observation revealed that at the anode site of a comparatively large sized cell:

1. The amount of visible light reached about 30 % of the total emitted light;
2. The Ne-visible-red light was not emitted from the anode,and;
3. The ratio of the infrared emitted light to the visible light was greater at the anode site than at the cathode site.

Furthermore, inside the Xe light emitting area the standing striation structure was observed to be similar to the striation seen in a positive column.

2.White Emission from the Multilayered-type Organic Electroluminescent device

Summary

Multilayered-type organic electroluminescent (EL) devices emitting white light were fabricated. The device having an ideal white chromaticity coordinates of CIE x,y = 0.33, 0.35 showed an external quantum efficiency of 1.19% when the current density was 1 mA/4 mm². It took almost 400 hours to become half value from the initial luminous intensity of 300 cd/m² when the device was driven by a constant current in vacuum.
The EL spectra changed with the increase of the applied current density to the device. There was also a spectra change with the passage of time when the device was continuously driven under a constant current . In both cases, the red part of white emission spectra decreased and the CIE coordinates shifted to the blue direction.

3.Development of a Projector using Photo-Conductive Liquid Crystal Light Valve (PCLCLV)

Summary

The authors have developed a projector using a photo-conductive liquid crystal light valve (PCLCLV). It uses a 1.1 inch TFT-LC-panel and LEDs for addressing, a metal-haride-lamp (250 W, DC) and two dichroic mirrors. It can project a video-rate full color picture up to 100 inches diagonal.
The authors carried out simulations taking into account the luminance radiation directivity distribution of a lamp and designed the light-source
system. The development of a liquid-type polarized-beam-spliter and correction of astigmatism by a cylindrical lens helped to obtain a bright ( 650 lumen) and distinct ( 60% at 400 TV lines-MTF) image.

4.Characteristics of Micromechanical Electrostatic Switch for Active Matrix Displays

Summary

The switching beam deflection of 0.16micro meter with the switching time of less than 100 nsec. was measured by a tightly focused laser interferometric method. Observed turn-on threshold voltages were more than 30 V, and the on/off hysteresis widths were from one third to two thirds of its threshold voltage.
The memory function was confirmed by applying the hold voltage of 25 V following on the writing pulse with the duration of 2 msec. and the amplitude of 32 V. A holding period of 2 msec. or longer has resulted which will lead to usage as an AM display device.

5.3D-CUBE System

Summary

The authors have developed a 3D-CUBE System and installed three systems in the Synthetic World Zone at the Aizu University. The system has 160 a inch diagonal screen, composed of sixteen rear-projection display units, each one being referred to as CUBE.
The junction borders of the individual CUBE units which used to appear as black stripes are made invisible.
The multi-scan 3D-CUBE system uses short afterglow CRTs and LCD shutters. The crosstalk of the system in 3D mode is less than 25 dB.

[General Paper]
System for alpha wave entrainment by Recorded Photic Stimulation

Summary

We developed a new system for alpha wave entrainment by recorded photic stimulation which has a relaxation effect and will introduce the user to sound sleep.
The alpha wave during sleep latency fluctuates its frequency, repeates its appearance and disappearance several times, and soon disappears completely. Such alpha wave data characterized by the flequency fluctuations are then taken in the photic signals generated by a photic-feedback. These signals are recoded in a memory and then replayed so that the brain wave pattern during the sleep latency is reproduced intending to reduce his/her arousal level.
The authors have developed an algorithm that defects the sleeping point and could idetify the sleeping point using the appearance rate of the burst alpha wave.
We definethe sleep latenncy as the three minutes prior to the point of sleep.
To test the feasibility of such an effect, we conducted a test for 28 adults who have a tendency of insomnia. As a result, we confirmed that there were improvements in such areas as the ease of getting to sleep, the perceived quality of sleep and the integrity of behavior following wakefulness.
The device incorporating the above mechanism is more suitable for use at bedtime compared with a conventional photic-feedback system because no annoying brain wave sensors need to be attached during the reproduction of the signal.