1. Field of the Invention
The present invention relates to an electron emission device, and in particular, to an electron emission device having cathode and anode electrodes, and a grid electrode disposed between the cathode and anode electrodes.
2. Description of Related Art
Generally, electron emission devices can be classified into two types. A first type uses a hot cathode as an electron emission source, and a second type uses a cold cathode as the electron emission source. Also, in the second type of electron emission devices, there are a field emission array (FEA) type, a surface conduction emitter (SCE) type, a metal-insulator-metal (MIM) type, a metal-insulator-semiconductor (MIS) type, and a ballistic electron surface emitter (BSE) type.
Although the electron emission devices are differentiated in their specific structure depending upon the types thereof, they all basically have an electron emission unit placed within a vacuum vessel to emit electrons, which strike phosphors on a phosphor layer to emit light. The electron emission device is employed for use in making a display apparatus, or other electronic appliances.
When the electron emission device displays a full-colored image with red, green, and blue phosphors, the electrons emitted from the electron emission unit at a specific pixel region should be focused on the correct phosphors at the relevant pixel while not being dispersed toward the incorrect phosphors at other pixels. Because of this, a metal mesh-shaped grid electrode is conventionally provided within the vacuum vessel forming the electron emission device.
The grid electrode has a structure where a plurality of electron beam guide holes are formed at a metallic plate by way of etching. The grid electrode is fitted between a first substrate with lower spacers and a second substrate with upper spacers.
However, with the electron emission device having the above-structured grid electrode, as the spacers are separately arranged below and above the grid electrode and are internally adhered to the vacuum vessel using an adhesive material, extra time and cost are consumed in installing these spacers, resulting in poor productivity.
Furthermore, with the conventional electron emission device, it is very difficult to attach the spacers to predetermined locations in a constant manner, and the spacers are likely to be displaced from the proper locations, and/or to be inclined. If the spacers are displaced and/or inclined, the support structure between the first and the second substrates is non-balanced, and is likely to be broken during the exhaust process.
In addition, with the conventional electron emission device, the spacers are installed using an adhesive material. When the adhesive material is partially vaporized during the sealing and exhaust processes while generating gas, it detrimentally affects the vacuum degree, and the vaporized gas needs to be exhausted.