 Environmental magnetism compensating device and cathode-ray tube display device |
| According to a first aspect of the present invention, an environmental magnetism compensating ... |
|
| Laser scanner driving apparatus |
| A laser scanner driving apparatus according to the present invention, wherein a rectilinear ... |
|
| Low driving voltage polymer dispersed liquid crystal display device with conductive nanoparticles |
| OF THE PREFERRED EMBODIMENT While the specification concludes with claims defining the features of ... |
|
| Multi-spot modulator using a laser diode |
| Referring now to FIG. 1, the preferred embodiment consists of a laser diode 1, a focussing lens 2 ... |
|
| Optical multiplexer |
| The object of the present invention is to provide a communications system capable of operation at ... |
|
| Broad-band ultraviolet lens systems well-corrected for chromatic aberration |
| We claim: 1. A lens system comprising a first rigid lens element, a second rigid lens element and a ... |
|
| Optical phase conjugator with spatially resolvable thresholding utilizing liquid crystal light valve |
| In view of the foregoing problems associated with the related art, it is a feature of the invention ... |
|
| Flat bed scanning type image reader |
| The general object of the present invention is to solve the problems of the known apparatus as ... |
|
|
Field emission electron gun
| Details |
Inventors: Sakitani, Yoshio;
Assignee: Hitachi, Ltd. (JA)
Primary Examiner: Rolinec; Rudolph V.
Assistant Examiner: Hostetter; Darwin R.
Attorney, Agent or Firm: Craig & Antonelli
A field emission electron gun capable of generating a highly stabilized electron beam, comprises a cathode tip for emitting electrons, an anode for attracting and accelerating the electrons, and means for heating the anode. A surface layer of the anode, which is to be bombarded by the electrons, consists essentially of getter material such as Zr-Al alloy. The anode heating means serves for heating the surface layer, so as to remove the absorbed gas molecules and to elevate the gettering effect of the getter material, whereby the absorbed gas molecules in the anode are hardly released therefrom, even if the anode surface is bombarded by the electrons. Therefore, the number of ions impinging on the cathode tip is remarkably reduced, and a stable electron beam can be obtained from the cathode tip. |
|
DETAILED DESCRIPTION It is therefore an object of the invention to provide a field emission electron gun capable of generating a stable electron beam for a long period of time.
A further object of this invention is to provide a field emission electron gun having a long life without any deformation and destruction of the cathode tip.
In order to accomplish these objects, the field emission electron gun according to the invention is characterized in that at least one part of the anode surface directly facing to the cathode tip (more particularly, at least one part of the anode surface which is to be bombarded by the electrons emitted from the cathode tip) is made of a getter material including at least one metal element selected from the group consisting of titanium (ti), zirconium (Zr), thorium (Th) and barium (Ba).
Also, anode heating means is provided for heating the anode surface so as to elevate the gettering effect of the getter material.
In the foregoing arrangement, the anode surface consisting of the getter material, which has been previously outgassed and activated by the heating means, strongly absorbs the residual gas in the vacuum.
The absorbed gas molecules in the activated getter material are hardly released from the anode surface when the anode surface is bombarded by electrons emitted from the cathode tip.
Therefore, the number of ions emanated from the anode surface is remarkably reduced.
Thus, ion impingement on the cathode tip is prevented, and a stable electron beam is obtained.
Other objects and features of the invention will be apparent from the following detailed description when read in conjunction with the accompanying drawings.
|
| Related patents |
|
|
Liquid crystal information storage and retrieval system
In accordance with the illustrated preferred embodiments, the present invention provides an optical, erasable, liquid crystal information storage and retrieval system. T...
|
|
|
Corona charging apparatus
In achieving the above and related objects, the invention provides a corona charging device comprising a support structure defining a slot in which a sheathed elongate ...
|
|
|
Substituted anthracene-type isotropic dyes for liquid crystal display devices
The isotropic dyes of this invention have the general formula: ##STR1## wherein W is selected from the group consisting of ##STR2## wherein: R is independently selected ...
|
|
|
Corona charging apparatus
In achieving the above and related objects, the invention provides a corona charging device comprising an elongate conductor with a dielectric sheath, and an overlying ...
|
|
|
Electron beam addressed liquid crystal light valve
OF PREFERRED EMBODIMENTS Referring to FIG. 1, a modified form of an LCLV is shown which provides a high resolution display of an electron beam scan pattern. A CRT is ...
|
|
|
Information writing method for an optical disc memory system utilizing a smectic chiral liquid crystal
It is therefore an object of the invention to provide an optical disc memory with liquid crystal. It is another object of the invention to provide an erasable and ...
|
|
|
Optical switches using ferroelectric liquid crystals
The invention comprises an optical switch wherein an input optical fiber directs light onto a first polarization means that polarizes the incoming light and directs it ...
|
|
|
Stereoscopic projector
Accordingly, it is an object of the present invention to provide a stereoscopic projector for overcoming such problems encountered in the conventional projectors. A...
|
|
|
Autostereoscopic display having a high resolution 2D mode
It is thus possible to provide an autostereoscopic display having enhanced resolution in a 2D mode. Advantageously the display may simultaneously display a 3D image and ...
|
|
|
N x N switch array with reduced components
Switch arrays are provided with controllable polarization modifiers and polarization-dependent diverters, such as one or more polarization beam splitters, for ...
|
|
|
LCD 
