CNT FED RGB Phosphor System for Brightness and Packing Density
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Solution Overview
Problem
Carbon nanotube/field emission device (CNT/FED) displays face challenges in achieving good color brightness and color gamut levels when operated below 4 kV, leading to decreased performance and degradation due to electron stimulated surface reactions of color-emitting phosphors.
Innovation Solution
A RGB phosphor system comprising ZnS:Cu (green), ZnS:Ag,Cl (blue), and Y2O2S:Eu+3 (red) phosphors with an average particle size of 3-4 microns is applied to the interior surface of the CNT/FED display, optimized for operation between 4-10 kV, using a manufacturing process involving a light-absorbing matrix and photosensitive layer deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If CNT/FED displays are operated below 4 kV, then power consumption is reduced, but color brightness and color gamut levels deteriorate and phosphor degradation occurs
Solution Approach 1:
The patent changes the operational voltage parameter to the optimal range of 4-10 kV, which resolves the contradiction by ensuring sufficient electron beam energy to excite phosphors effectively for good color brightness while maintaining reasonable power consumption through efficient electron-phosphor interaction at this voltage range
Solution Approach 2:
The patent employs a specific RGB phosphor system with carefully selected phosphors (ZnS:Cu,Al for green, ZnS:Ag,Cl for blue, Y2O2S:Eu+3 for red) with optimized particle sizes of 3-4 microns. This phosphor composition enables effective luminescence excitation at 4-10 kV operating voltage, achieving good color brightness and gamut while preventing phosphor degradation that would occur at lower voltages
2Manufacturing precision
If phosphor particle size is reduced to improve resolution, then packing density decreases, but manufacturing precision improves
Solution Approach 1:
The patent optimizes the phosphor particle size parameter to 3-4 microns, which is large enough to maintain high packing density and efficient luminescence, yet small enough to achieve good resolution and color purity. This specific size range resolves the contradiction between manufacturing precision and packing density by finding the optimal balance point
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The RGB phosphor system enhances color brightness and gamut levels, matching or exceeding the efficiency of standard CRT materials, while minimizing phosphor overlap and ensuring efficient packing density, thus improving display performance within the specified voltage range.
Implementation Method 1
The phosphor screen is located on an inner surface of a faceplate of the display. The metal gate functions to direct electron beams generated from the CNT emitters toward appropriate color-emitting phosphors on the screen of the display.
Implementation Method 2
Each of the color-emitting phosphors is separated from another by a matrix line. The matrix lines are typically formed of a light-absorbing black, inert material.
Data Source
AI summary
A RGB phosphor system for a carbon nanotube (CNT)/field emission device (FED) display operated between about 4-10 kV. The RGB phosphor system is formed on an interior surface of a screen of the CNT/FED display. The RGB phosphor system includes ZnS:Cu, Al (green phosphor), ZnS:Ag,Cl (blue phosphor) and Y2O2S:Eu+3 (red phosphor). The average particle size for each of the green, blue and red phosphors should be about 3-4 microns.