Carbon-Nanotube-Based Normally-on-Driving Under-Gate Field Emission Display Panel

A carbon-nanotube-based normally-on-driving under-gate field emission display(FED)panel and its operation principle are presented.In this panel,field emission electrons are extracted directly from the cathode by the high anode voltage.The image is realized by modulating the voltage of under-gate,whose value is less than the cathode voltage,to stop the cathode producing field emission electrons.The electric field inside the emission region is calculated by the finite element method.The emission property of the cathode is also studied by numerical calculation method.The results indicate that a uniform and large emission area can be obtained in this new under-gate FED panel.This study provides powerful theoretic support for the feasibility of this new kind of under-gate FED panel.

Power consumption in a field emission panel

The power consumption and electric field distribution in a field emission display （FED） panel is optimized with a novel pixel structure. A circuit model is proposed to estimate the total power consumption in an FED panel which is composed of anode energy consumption, energy loss due to the leakage current and the energy dissipated in the parasitic capacitances. Moreover, the parasitic capacitances play a vital part in the power consumption and driving performance. In order to lower the parasitic capacitances, multiple dielectric layers are used as the gate electrode. Due to different etching speeds, a novel pixel structure is formed. As a result, the power consumption of an FED panel is reduced by 28% in a full white picture, and the electron beam performance is also better than that of the conventional structure.

Field emission digital display tube with nano-graphite film cathode

The field emission digital display tube with a nano-crystalline graphite cold cathode is designed and fabricated. Under the control of the driving circuits, a dynamic digital display with uniform luminance distribution is realized. The luminance of the character segments is 190 cd/m2 at the operating voltage of 900 V. And the stable emission is attained with a fluctuation of about 3% at an average segment current of 75 μA. The results demonstrate that nano-crystalline graphite film is a promising material for cold cathode.

New type gate electrode of CNT-FED fabricated by chemical corrosive method

To obtain a triode structure canbon nanotube field emission display （CNT-FED）, the glass plate which contains a glass channels matrix is designed and used as the triode part of the CNT-FED. Normally, the gate electrode can be fabricated with screen printing methods and a channels matrix can be fabricated by two- faced chemical corrosion. By adjusting the etch time and the concentration of acid in the process, different shapes of the tunnels can be obtained. The size and morphology of channels are observed by a scanning electron microscope （SEM）, and the ingredients of the corrosion solution are detected by infrared ray （IR） analysis. Voltage is added to the triode structure for obtaining the brightness image of the spot on the screen. Eventually, the electron trace pulling from cathode to anode under an electric field is obtained by simulation. It is concluded that the simulation results accord with the experimental results which realize the optimized triode structure.

Carbon nanotube emitters and field emission triode

Based on our study on field emission from multi-walled carbon nanotubes （MWNTs）, we experimentally manufactured field emission display （FED） triode with a MWNTs cold cathode, and demonstrated an excellent performance of MWNTs as field emitters. The measured luminance of the phosphor screens was 1.8 × 10^3 cd/m^2 for green light. The emission is stable with a fluctuation of only 1.5% at an average current of 260 μA.

INFLUENCE OF ELECTRICAL AND STRUCTURAL PARAMETERS ON THE PERFORMANCE OF THE SPACERS IN HOPFED

The HOPping Field Emission Display （HOPFED） is a new architecture for field emission displays. The main difference between a conventional Field Emission Display （FED） device and a ItOPFED lies in the spacer structure. In a HOPFED, two dielectric plates, named hop and flu spacer, are sandwiched between the emitter and the front plate. The objective of this spacer structure is to improve the performance oF a FED substantially with notable contrast, color purity and luminance uniformity. In order to optimize the structure of the device and to make the electron spot on the screen match the requirement of the phosphor dot dimension, the influence of electrical and structural parameters of the device on the electron spot profile was studied by numerical simulation in this paper. Monte Carlo method was employed to calculate the potential distribution inside hop and flu spacers due to secondary electrons mechanism plays an important role in HOPFED. The results indicated that the potential distribution in the spacers and spot profile depended strongly on the hop voltage, anode voltage and spacer＇s layout. This study may provide a useful theoretical support for optimizing the structure in HOPFED.

Seeking new,ultra-narrow-band blue emitting phosphors with high color purity for wide color gamut displays

Ultra-narrow-band phosphors have gained widespread applications in lighting and displays to enhance brightness and improve color saturation.Typical phosphor designs employ UCr_(4)C_(4)-type compounds and designing new narrow-band phosphors with high color purity is a major challenge.Here,we explored a Eu^(2+)-doped Ba_(5)GeO_(4)Br_(6)phosphor,showing a narrow-band blue emission(λ_(em)=436 nm) excitation at the near-ultraviolet light with a full width at half maximum of 30.7 nm and high color purity of 96.6%.In addition,attractive cathodoluminescence characteristics were systematically analyzed by varying filament current(30-70 mA) and accelerating voltage(3-7 eV).Robust anti-degradation behavior and color point stability under continuous electron beam bombardment were confirmed.Given its excellent performance in photoluminescence and cathodoluminescence,application in wide color gamut displays appears promising.Using commercial phosphors β-SiAlON:Eu^(2+)and K_(2)SiF6:Mn^(4+)as green and red light co nverte rs respectively,and the title phosphor as the blue light converters,the fabricated w-LED exhibits a wide color gamut of 82% NTSC.