Cathodoluminescent Characteristics of a Spherical Y[sub 2]O[sub 3]:Eu Phosphor Screen for Field Emission Display Application

Abstract

The cathodoluminescent characteristics (CL) of a spherical Y 2 O 3 :Eu phosphor screen were investigated for field emission display application. The phosphor screen as an anode plate was vacuum sealed (ϳ3 ϫ 10 Ϫ6 Torr) with 0.7 in. diagonal Si-based Mo tip field emitter array with 25 ϫ 25 pixels. It was prepared by electrophoretically depositing spherical Y 2 O 3 :Eu phosphors, which were synthesized by the aerosol pyrolysis method. The character image was displayed on this anode plate by an external driver circuit with PWM driving scheme. The CL brightness of 41 cd/m 2 with CIE chromaticity of x ϭ 0.649, y ϭ 0.346 could be obtained at 400 V anode voltage and 55 V gate voltage inducing a 48 A/cm 2 current density in the dc mode, corresponding to 0.63 lm/W. However, screen efficiency could be increased to 1.24 lm/W by reducing the charge dose on the screen, of which the operating conditions were of 400 V anode voltage and 60 Vp-p gate voltage inducing an average 30 A/cm 2 emission current density in 15% pulse mode. It was found that the electrical resistivity of the phosphor screen was the origin of a pool image of displayed character and even caused a sudden decrease of emission light. The charging effects of spherical Y 2 O 3 :Eu phosphors screen on the luminance under low voltage operation are examined in this work and the methodology for enhancing picture quality is discussed based on experimental observation.

Cathodoluminescence of Powder Layers of Nanometer-Sized Y2O3:Eu and Micrometer-Sized ZnO:Zn Phosphor Particles

“…6,8,9 The difficulties in measuring the lumen efficacy and energy efficiency (sometimes called quantum efficiency) of low-voltage phosphors can be appreciated from the spread of published values by Shea, 10,11 11 Charging of Y 2 O 3 :Eu could be the reason for the rather large spread in the luminous efficacy of Y 2 O 3 :Eu. Varying the bias voltage of sample or shield provides information on the charging condition of a surface that is bombarded with electrons.…”

“…6,8,9 The difficulties in measuring the lumen efficacy and energy efficiency (sometimes called quantum efficiency) of low-voltage phosphors can be appreciated from the spread of published values by Shea, 10,11 Yang et al, 12 Wakefield et al 13 and Dmitrienko et al 14,15 These latter authors stated that charging of ZnO:Zn at low current density is less of an issue, because changes of the CL efficacy 1 This measuring method was applied to determine whether our layers were charging or not.…”

Tunable Cathodoluminescence Properties of Tb[sup 3+]-Doped La[sub 2]O[sub 3] Nanocrystalline Phosphors

“…9 The demand for high resolution and increased efficiency in phosphors for FEDs has promoted the development of phosphors that perform at low voltages. [10][11][12][13][14] Many efficient sulfide-based phosphors, such as Y 2 O 2 S:Eu, Gd 2 O 2 S:Tb, SrGa 2 S 4 :Eu, Zn͑Cd͒S:Cu,Al, ZnS:Ag,Cl, etc., have been explored as possible low voltage phosphors. [15][16][17][18] Unfortunately, sulfide phosphors are easy to decompose and to emit sulfide gases under the electron excitation, subsequently causing the cathodes to deteriorate, thus lowering the lifetime and luminous efficiency of phosphors.…”

Structural Analysis of CaLaAlO4 Powder via Solid State Method

“…Calcium Lanthanum Aluminate (CLA) has a tetragonal K 2 NiF 4 structure and belongs to a family of compounds with the general formula XYZO 4 , where X is an alkaline earth cation, Y is La, Sc, or a trivalent rare-earth element and Z is Al, Ga or a transition metal ion. Its crystal structure consists of interleaved layers with a perovskite and rock-salt structure.…”