Thursday, November 20, 2008
17 are the Spindt tips >>>>>>>>>>>>>>>>>>Click pics for enlarged view
21 are the CNTs
I looked Sony's US patents up and found this US patent 7,329,978 :
Specifically, the carbon-nanotube structure includes a carbon-nanotube and/or a carbon-nanofiber. More specifically, the electron-emitting portion may be constituted of a carbon-nanotube, it may be constituted of a carbon-nanofiber, or it may be constituted of a mixture of a carbon-nanotube with a carbon-nanofiber. Macroscopically, the carbon-nanotube and carbon-nanofiber may have the form of a powder or a thin film. The carbon-nanotube structure may have the form of a cone in some cases. The carbon-nanotube and carbon-nanofiber can be produced or formed by a known PVD method as an arc discharge method and a laser abrasion method; and any one of various CVD methods such as a plasma CVD method, a laser CVD method, a thermal CVD method, a gaseous phase synthetic method and a gaseous phase growth method.
In the plane-type field emission device, as a material for constituting an electron-emitting portion, particularly, carbon is preferred. More specifically, diamond, graphite and a carbon-nanotube structure are preferred.
The method of manufacturing the Spindt-type field emission device will be explained below with reference to FIGS. 17A, 17B, 18A and 18B which are schematic partial end views of the supporting member 10, etc., constituting a cathode panel.
The above Spindt-type field emission device can be obtained basically by a method in which the conical electron-emitting portion 17 is formed by vertical vapor deposition of a metal material. That is, while deposition particles perpendicularly enter the opening portion 16A formed through the focus electrode 15, the amount of deposition particles reaching the bottom portion of the opening portion 16 is gradually decreased by utilizing a masking effect produced by an overhanging deposit formed around the edge of opening of the opening portion 16A, and the electron-emitting portion 17, which is a conical deposit, is formed in a self-alignment manner. There will be explained below a method in which a peeling-off layer 19A is formed on the focus electrode 15 beforehand for making it easy to remove an unnecessary overhanging deposit. In the drawings for explaining the method of manufacturing a field emission device, one electron-emitting portion alone is shown.
An electron-emitting portion 17A comprises a matrix 20 and a carbon-nanotube structure (specifically, a carbon-nanotube 21) embedded in the matrix 20 in a state where the toportion of the carbon-nanotube structure is projected, and the matrix 20 is made of an electrically conductive metal oxide (specifically, indium-tin oxide, ITO). [See Fig. 20 - no cones! But vertically arranged CNTs are aligned across the bottom of the emitter chamber in matrix 20]
From Sony's US patent 7,329,978:
So - the cone emitters can be molded entirely from CNTs! Or the emitters may be CNTs in a planar layer at the bottom of the emitter well. We will see what this amazing FED display actually contains some day! I have no doubts myself that CNTs are at the heart of it!!!!
See also United States Patent Application 20070196564