A study on the chromaticity shifts of blue phosphor for color plasma displays

The dependency of the chromaticity shifts on the concentration of Eu²⁺ doped in BaMgAl₁₀O₁₇ (BAM) was investigated under heat‐treatment and vacuum ultraviolet (VUV) irradiation. The Eu²⁺ ions in BAM show an asymmetrical broad emission band with a maximum at ～452 nm under excitation of VUV light at room temperature, showing that multiple crystalline cationic sites exist in the host. It was found that the chromaticity shifts greatly decrease with increasing heat‐treatment temperature. Regardless of the Eu²⁺ concentration, the chromaticity shifts caused by heat‐treatment are greater than that caused by VUV irradiation. Compared with conventional BAM, a solid solution of BAM with barium aluminate as a powder and film was also studied, and very few chromacity shifts were observed. It is suggested that the distribution of Eu²⁺ ions in different sites in a BAM lattice results in different chromaticity coordinates. By increasing the Eu²⁺ concentration in BAM, or under heat‐treatment and VUV irradiation, the emission band shifts towards longer wavelengths.     

New high‐luminance 50‐ and 43‐in. ACPDPs with an improved panel structure

New 50‐ and 43‐in. ACPDPs, which have been developed and commercialized in 2001, show high luminance with improved cell structure and higher Xe‐content gas. The specific features of the cell structure are “T”‐shaped electrodes and waffle‐structured ribs, which are same as those of the previous model. Both the cell structure and gas conditions have been optimized. New green and blue phosphors have also been adopted. As a result, the luminous efficacy has been improved up to 1.8 lm/W by using a black stripe. The peak luminance of the 50‐ and 43‐in. PDPs have reached 900 and 1000 cd/m², respectively, while the power consumption of the 50‐in. PDP has been decreased to 380 W, which is 20% lower than that of our previous 50‐in. PDP.     

Development of a high‐definition 32‐in. PDP

We developed the world's smallest‐profile 32‐in. HDTV PDP. By improving the luminous efficiency, a luminance of 650 cd/m² and power consumption (discharge and driving circuit) of 200 W or less was achieved. Moreover, incorporating an advanced color compensating (ACC) filter improved the PDP's color‐reproduction capability, better than that of CRTs.     

等离子体显示技术的进展

概述了等离子体显示技术的研究进展,着重讨论了彩色等离子体显示中在提高发光效率和亮度、提高对比度等方面的最新技术。     

Discharge characteristics of plasma display panels with Si-doped MgO protective layers

We report on our study of the influence of varying concentrations of Si doping on the secondary electron emission (SEE) yield of MgO thin films prepared by electron beam evaporation technique. The series of Si-doped MgO films were microstructurally characterized with various tools like X-ray diffraction, scanning electron microscopy and atomic force microscopy. The optimization of the concentration of Si doping is seen to enhance the SEE yield. We discuss the correlation of SEE yield in the context of different deposition and measurement conditions and crystalline orientation.     

Application of AC plasma display panels to radiation detectors

Radiation detector proposals that use plasma display panels are rare. In this work, we confirmed a radiation detector that uses plasma display panels that are focused on the breakdown voltage shift in the ramp waveform. We adapted the cell structures, gas contents, and waveforms of plasma display panels (AC‐PDPs) for radiation detectors. Hard X‐rays and gamma rays induce electron emission into the discharge gas, resulting in generating electrons, electron multiplication, and charge accumulation on dielectrics. The radiation dose rate of hard X‐rays and gamma rays (Cs137) is measured as a breakdown voltage shift between anodes and cathodes. For gamma rays, the detection sensitivity in this experiment is not as high as in the case of hard X‐rays, but the detector can locate gamma rays. These results suggest that adapted AC‐PDPs can detect both hard X‐rays and gamma rays and can be used in a large two‐dimensional radiation detector.     

A Basic Chemical Synaptic Euler Model and Its Triad Trigger Topology

To deeply understand neuromorphic elec-tronic systems, a basic chemical synapse model is given by logistic Euler inverse mapping and transformation in tandem, 3T-MOS triod-trigger-topology (3T3) is designed in sub-threshold region at 100mV supply for compact synaptic circuit, and the power consumption of synapse in brain-circuitry (ion-bump-city) is compared with its five mimic blocks of HfOx/AlOx typed memristor, modified 2T-MOS-K+-bump circuit, 3T3 synaptic circuit and 4T-Schmitt-oscillator based synaptic circuit, and Chua's cir-cuit on Power-delay-products' (PDP) levels. Above works will match searching for novel feature operators during pushing forward brain health microelectronics.     

A new perspective for the thermal degradation mechanism of blue BAM

A new thermal degradation mechanism for blue BAM (BaMgAl₁₀O₁₇:Eu²⁺) under thermal treatment in the presence of water is proposed. The water can be originated either from the thermal treatment steps, such as organic binder baking steps, or from the atmosphere under which blue BAM is being heated. Under such thermal treatment conditions, water molecules can be easily intercalated into the conduction layers of blue BAM, resulting in not only the depreciation of luminance but also in the emission color change toward green. The intercalated water molecules in the conduction layer, where Eu²⁺ ions are located along with Ba²⁺ ions, are strongly associated with Eu²⁺ ions, creating different coordination environments around Eu²⁺ ions. In this paper, the details of changes in emission behaviors along with water content in the water intercalated blue BAMs are discussed.     

Radio‐frequency plasma‐display cell

Abstract— This paper demonstrates that it is possible to improve the basic parameters of plasma displays (efficiency, primarily) using AC voltages with frequencies so high that the amplitude of the electron‐drift oscillations is smaller than the inter‐electrode gap. In this case, the voltage drop on sheaths is much smaller than that in the low frequency or DC discharge and, correspondingly, the energy losses in ion heating are also small. Electron losses in the RF discharge are of the diffusion character and sufficiently lower than the losses in a typical AC plasma‐display panel (AC PDP), in which the electron drift to the electrodes is predominant. Hence, the energy cost of gas ionization in the cells of radio‐frequency PDPs (RF PDPs) is also rather low. In the long run, about 80% of the energy absorbed in the RF discharge goes into excitation of the energy level of a Xe atom, yielding UV radiation. The experiments performed show that efficiency of a RF PDP is five times higher than the efficiency of existing AC PDPs and DC PDPs and can exceed 5 lm/W.     

High‐luminance and highly luminous‐efficient AC‐PDP with DelTA cell structure

To improve PDP performance, we developed an AC‐PDP with the Delta Tri‐Color Arrangement (DelTA) cell structure and arc‐shaped electrodes. The experimental panel has a pixel pitch of 1.08 mm and luminous efficacy of 3 lm/W at a luminance of 200 cd/m² despite its conventional gas mixture of Ne and Xe (4%) and conventional phosphor set. Moreover, its peak luminance can be greater than 1000 cd/m². The strong dependence of luminous efficacy on the sustain voltage is also discussed in this paper.