The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which:
The present invention is described more fully below with reference to the accompanying drawings in which exemplary embodiments of the present invention are shown. In the drawings, the thicknesses of layers and regions are exaggerated for clarity, and like reference numerals refer to the like elements. An FED according to the present invention described hereinafter can be used as a display in various fields, and can also be used as a backlight unit of an LCD.
Referring to
The cathode panel 110 includes a lower substrate 111, a cathode electrode 113, an insulating layer 115, and a gate electrode 117, which are sequentially arranged on the lower substrate 111. The lower substrate 111 can be a transparent glass substrate or can be a plastic substrate. The cathode electrode 113 can be arranged in a predetermined shape, for example, a stripe shape on an upper surface of the lower substrate 111, and can be of a transparent conductive material, for example, Indium Tin Oxide (ITO).
The insulating layer 115 covering the cathode electrode 113 is arranged on the lower substrate 111. The insulating layer 115 has a plurality of emitter holes 118 that expose the cathode electrode 113. Emitters 119, which are electron emission sources, are respectively arranged in the emitter holes 118. Each of the plurality of emitter holes 118 can be arranged to correspond to one of pixels 130R, 130G, and 130B. The emitters 119 can be made of Carbon NanoTubes (CNTs) having high electron emission characteristics. However, the present invention is not limited to CNTs. That is, the emitters 119 can be of various materials.
The gate electrode 117 for extracting electrons is arranged on an upper surface of the insulating layer 115. The gate electrode 117 can be arranged to cross the cathode electrode 113. The gate electrode 117 can be of a conductive metal or a transparent conductive material, for example, ITO. Although not shown, a resistance layer can further be arranged on an upper or a lower surface of the cathode electrode 113 to make uniform a current emitted by the emitters 119.
The anode panel 120 includes an upper substrate 121 disposed a predetermined distance apart from the lower substrate 111, and an anode electrode 123, a black matrix 125, phosphor layers 127R, 127G, and 127B, and a reflection layer 129 sequentially arranged on the upper substrate 121. The upper substrate 121 can be a transparent glass substrate or a transparent plastic substrate. The anode electrode 123 is arranged on a lower surface of the upper substrate 121. The anode electrode 123 can be arranged to cover the entire lower surface of the upper substrate 121. The anode electrode 123 can be of a transparent conductive material, for example, ITO, so that visible light emitted from the phosphor layers 127R, 127G, and 127B can pass therethrough.
The black matrix 125 is arranged on a lower surface of the anode electrode 123. The black matrix 125 has a plurality of openings 125a that expose the anode electrode 123. In other FEDs, one opening is arranged to correspond to one pixel, but in this embodiment of the present invention, multiple openings 125a are arranged to correspond to one of the pixels 130R, 130G, and 130B. The black matrix 125 having the multiple openings can increase contrast and can increase uniformity of brightness in each of the pixels 130R, 130G, and 130B by reflecting visible light generated by the phosphor layers 127R, 127G, and 127B, as will be described later. The black matrix 125 can be made of Cr or chromium oxide. In
The phosphor layers 127R, 127G, and 127B of predetermined colors, for example, red R, green G, and blue B color, are arranged on a lower side of the black matrix 125. Each of the phosphor layers 127R, 127G, and 127B that constitutes one pixel 130R, 130G, and 130B is arranged to cover the openings 125a corresponding to each of the pixels 130R, 130G, and 130B and the black matrix 125 between the openings 125a. The phosphor layers 127R, 127G, and 127B in the pixels 130R, 130G, and 130B generate visible light having a predetermined color due to collision with electrons emitted by the emitters 119 arranged on the cathode panel 110. The reflection layer 129 is arranged on lower surfaces of the phosphor layers 127R, 127G, and 127B. The reflection layer 129 reflects visible light generated by the phosphor layers 127R, 127G, and 127B towards the upper substrate 121. The reflection layer 129 can be of a material having high reflectance, for example, aluminum.
In an FED having the above structure, when a predetermined voltage is supplied to each of the cathode electrodes 113, the gate electrodes 117, and the anode electrodes 123, electrons are emitted from the emitters 119 and proceed towards the anode electrode 123s due to an electric field arranged between the cathode electrodes 113 and the gate electrodes 117. As depicted in
Some portion of the visible light generated by the phosphor layers 127R, 127G, and 127B is directly emitted to the outside through the openings 125a after passing through the anode electrode 123 and the upper substrate 121, or emitted to the outside through the openings 125a after passing through the anode electrode 123 and the upper substrate 121 after being reflected once by the reflection layer 129. The other portion of the visible light, as depicted in
Referring to
The cathode electrode 213 is arranged in a predetermined shape on an upper surface of the lower substrate 211. The insulating layer 215 is arranged to cover the cathode electrode 213. A plurality of emitter holes 218 that expose the cathode electrode 213 are arranged in the insulating layer 215. Emitters 219, which are electron emission sources, are respectively arranged in the emitter holes 218. A plurality of emitters 219 can be arranged to correspond to one pixel 230R, 230G, and 230B. The emitters 219 can be made of CNTs having high electron emission characteristics. However, the material for forming the emitters 219 is not limited to CNTs, that is, the emitters 219 can be of various materials other than CNTs. The gate electrode 217 for extracting electrons is arranged in a predetermined shape on an upper surface of the insulating layer 215. Although not shown, a resistance layer can further be arranged on an upper surface of the cathode electrode 213 to obtain a uniform current generated by the emitters 219.
The anode panel 220 includes an upper substrate 221, an anode electrode 223, a black matrix 225, phosphor layers 227R, 227G, and 227B, a first reflection layer 229, and a second reflection layer 226. The upper substrate 221 is disposed a predetermined distance apart from the lower substrate 211 and faces the lower substrate 211. The upper substrate 221 can be a transparent glass substrate or a transparent plastic substrate. The anode electrode 223 is arranged on a lower surface of the upper substrate 221. The anode electrode 223 can be arranged to cover the entire lower surface of the upper substrate 221. The anode electrode 223 can be of a transparent conductive material, for example, ITO.
A black matrix 225 is arranged on a lower surface of the anode electrode 223 to increase contrast. The black matrix 225 has a plurality of first openings 225a that expose the anode electrode 223. Each of the first openings 225a corresponds to each pixel 230R, 230G, and 230B. The black matrix 225 can be of, for example, Cr or chromium oxide.
The phosphor layers 227R, 227G, and 227B of red R, green G, and blue B colors are sequentially filled in the first openings 225a of the black matrix 225. The first reflection layer 229 is arranged on lower surfaces of the phosphor layers 227R, 227G, and 227B. The first reflection layer 229 reflects visible light generated by the phosphor layers 227R, 227G, and 227B so that the visible light can proceed towards the upper substrate 221. The first reflection layer 229 can be of a material having high reflectance, for example, aluminum.
The second reflection layer 226 is arranged on an upper surface of the upper substrate 221. The second reflection layer 226 has a plurality of second openings 226a to expose the upper substrate 221. In the present embodiment, multiple second openings 226a correspond to one pixel 230R, 230G, and 230B. The second reflection layer 226 can be of the same material as that of the black matrix 225. More specifically, the second reflection layer 226 can be made of, for example, Cr or chromium oxide. Also, the second reflection layer 226 can be of aluminum as with the first reflection layer 229. The second reflection layer 226 having multiple second openings 226a increases the brightness uniformity in the pixel 230R, 230G, and 230B by reflecting visible light generated by the phosphor layers 227R, 227G, and 227B, as described later. In
In the FED having the above structure, when a predetermined voltage is supplied to each of the cathode electrodes 213, the gate electrodes 217, and the anode electrodes 223, electrons are emitted from the emitters 219 and proceed towards the anode electrodes 223 due to an electric field between the cathode electrodes 213 and the gate electrodes 217. As depicted in
Some portion of the visible light generated by the phosphor layers 227R, 227G, and 227B is directly emitted to the outside through the second openings 226a after passing through the anode electrodes 223 and the upper substrate 221 or emitted to the outside through the second openings 226a after being reflected once by the first reflection layer 229 and passing through the anode electrodes 123 and the upper substrate 121. The other portion of the visible light, as depicted in
As described above, according to the present invention, although electron emission from the emitters is not uniform, the brightness uniformity in pixels of an FED can be greatly increased by multi reflecting visible light emitted by the phosphor layers.
While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various modifications in form and detail may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.
Number | Date | Country | Kind |
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10-2006-0098642 | Oct 2006 | KR | national |