1. Field of the Invention
The present invention generally relates to an image display apparatus.
2. Description of the Related Art
There has recently been increasing demand for image display apparatus (e.g., displays) that show additional improvements in their performance, size, and image quality, in association with the diversification and densification of image information. In particular, with the growing concern for energy savings and space savings, there has been a shift from demand for image display apparatus that use a cathode ray tube, called a Braun tube, to a demand for flat panel displays. Hereinafter, the cathode ray tube is abbreviated as “CRT”, and the flat panel display is abbreviated as “FPD”.
Examples of the FPD include a liquid crystal display, a plasma display and a field emission display (hereinafter abbreviated as “FED”). The FED is an image display apparatus that generally operates on the following principle: fine electron-emitting devices, the number of which is equal to that of the pixels, are placed on a substrate, and electrons are emitted from the electron-emitting devices into a vacuum, and are caused to impinge on a phosphor to cause the phosphor to emit light. Each of the electron-emitting devices corresponds to the electron gun of a Braun tube, and can realize a fairly bright image having a sufficiently high contrast on a relatively large flat panel display, as in the case of a CRT, and thus the FED is expected to show promise as a next-generation self light-emitting FPD.
An available technique for producing an FED involves the use of, for example, an electron-emitting device of a type called a Spindt type in which an electron is emitted from the tip of the cone of a conical emitter, or a device of a planar structure called a surface-conduction electron-emitter. Hereinafter, the surface-conduction electron-emitter is abbreviated as “SCE”, and a surface-conduction electron-emitter display is abbreviated as “SED”.
In an FED of such a type that a phosphor is caused to emit light by accelerating an electron at a relatively high voltage, a P22 type phosphor for a conventional CRT is often used, either as it is or after a certain improvement.
For example, in an FED of such a type that a phosphor is caused to emit light by accelerating an electron at a relatively high voltage, ZnS:Ag (blue phosphor), ZnS:Cu (green phosphor) and Y2O2S:Eu3+, referred to as YOS hereinafter (red phosphor) are generally used, and are also called P22 type phosphors, each of which has established some achievement in CRT applications.
However, when one tries to display a high definition television (HDTV) image with an FED using a P22 type phosphor, the resulting motion image may be inferior in visibility as compared to that in the case of a CRT type image display apparatus.