VACUUM ENVELOPING COMPONENT FOR VACUUM-BASED ELECTRONIC DEVICES AND METHOD OF FABRICATION THEREOF

Abstract

The apparatus and method of the present invention provide an improved low cost and easy to manufacture vacuum-proof shatter-resistant enveloping component, having superior temperature stability, as well as high temperature and mechanical reliability, that is readily usable with any electronic/thermoelectric device that utilizes enveloped vacuum in the operation thereof. In accordance with various embodiments of the present invention, rather than being made from a single layer glass or a ceramic material, the novel vacuum enveloping component comprises a hollow housing fabricated from a thermo-stable metal alloy, and provided with an inner insulating layer composed of a non-conductive material.

Description

CROSS REFERENCE TO RELATED APPLICATION

The present patent application claims priority from the commonly assigned co-pending U.S. provisional patent application 61/421,860 entitled “IMPROVED VACUUM ENVELOPING COMPONENT FOR VACUUM-BASED ELECTRONIC DEVICES AND METHOD OF FABRICATION THEREOF”, filed Dec. 10, 2010.

FIELD OF THE INVENTION

The present invention relates generally to vacuum-based/thermoelectric electronic devices, and more particularly to high reliability vacuum-proof enveloping components usable with various electronic devices that utilize enveloped vacuum in their operation.

BACKGROUND

Various electronic and electro-thermal devices that utilize vacuum in their operation (hereinafter “vacuum-based devices”) have been in use for decades. The most commonly used, and most well-known, vacuum-based deices are vacuum tubes (also referred to as electron tubes, and/or as thermionic valves) that are utilized to amplify, switch, otherwise modify, or create an electrical signal by controlling the movement of electrons in a low-pressure space—i.e. the vacuum region surrounded by the tube's vacuum-enveloping component.

Referring to FIG. 2, a conventional previously known vacuum-based electronic/thermo-electric device, is shown as a vacuum-based device 50, having a base/interface component 52 configured for connection to an electrical interface (e.g., to a socket, etc.), and an active component 54, operable to provide the designated electrical signal modification functionality of the device 50, that is surrounded by a vacuum 58 sealed-in and enveloped by a vacuum-proof housing 56, which is composed of glass or an equivalent ceramic material. Conventional vacuum-proof housings, such as housing 56, are currently made from glass or ceramic materials primarily due to their relatively high thermal stability and their ability to form a fairly reliable seal with the device base.

However, all vacuum-based devices that utilize glass or ceramic materials as the vacuum-enveloping components suffer from a number of significant disadvantages:

• • (1) glass/ceramic vacuum-enveloping housings are difficult and expensive to manufacture;
  • (2) glass/ceramic vacuum-enveloping housings are notoriously fragile and are prone to catastrophic failure that makes the device unusable.
    • (a) For example, a crack in the glass envelope housing will allow air into the device and destroy it. Cracks may result from stress in the glass, bent pins (of the device base), or from impacts to device.
    • (b) Moreover; device bases (e.g., sockets) must allow for thermal expansion, to prevent stress in the glass housing at the pins. Stress may accumulate if a metal shield or other object presses on the glass envelope housing and causes differential heating of the glass.
    • (c) Glass envelope housing may also be damaged by high-voltage arcing in the device;
  • (3) one of the greatest challenges in design and fabrication of conventional vacuum-based devices, is the proper selection of materials for the metal bases (e.g. sockets, pins, etc.) and for glass/ceramic vacuum-enveloping housings, that have matching or very similar thermo-expansion factors to prevent the glass/ceramic material from cracking around device pins or at the interface with the device base). While there are “workable” material pairings known in the field, the temperature ranges thereof are very narrow (e.g., about 200 degrees Celsius for glass). This problem also limits options for design of new or customized vacuum-based devices.

BRIEF DESCRIPTION OF THE DRAWING

In the drawings, wherein like reference characters denote corresponding or similar elements throughout the various figures:

FIG. 1 depicts an exemplary embodiment of the inventive improved vacuum-proof enveloping component implemented in an exemplary vacuum-based electronic/thermo-electric device; and

FIG. 2 shows a conventional previously known vacuum-based electronic/thermo-electric device utilizing a glass or ceramic vacuum-enveloping component.

DETAILED DESCRIPTION

The apparatus and method of the present invention address the various flaws and drawbacks of previously known vacuum-based electronic/thermo-electric devices (such as conventional vacuum tubes, etc.). The inventive apparatus and method advantageously provide an improved low cost and easy to manufacture vacuum-proof shatter-resistant enveloping component, having superior temperature stability, as well as high temperature and mechanical reliability, that is readily usable with any electronic/thermoelectric device that utilizes enveloped vacuum in the operation thereof. In accordance with various embodiments of the present invention, rather than being made from a single layer glass or a ceramic material, the novel vacuum enveloping component comprises a hollow housing fabricated from a thermo-stable metal alloy (such as an aluminum-based alloy—e.g., duraluminum), and provided with an inner insulating layer composed of a non-conductive material (deposited on the inner surface of the housing via any appropriate process, such as by application of a physical or electrostatic coating, physical vapor deposition, micro-arc oxidation, etc.).

FIG. 1 depicts an exemplary embodiment of the inventive improved vacuum-proof enveloping component implemented in an exemplary vacuum-based electronic/thermo-electric device 10. The vacuum-based device 10 includes a base/interface component 12 which may be composed of any desired material and which includes various interface elements (e.g., pins, etc.), and also includes at least one active component 14 (at least a portion of which may optionally extend into, and be disposed in, the base/interface 12) that is operable to provide device 10 primary functionality—e.g., amplification, switching, or other modification of an electronic signal, etc. Advantageously, the device 10 also includes a novel vacuum-enveloping hollow housing 16 that is mounted on, or otherwise securely connected to, the base/interface 12, in a manner that seals in a vacuum 18 disposed around the active component 14.

Preferably, the novel housing 16 comprises an outer housing layer 16a fabricated from a thermo-stable metal alloy (such as an aluminum-based alloy—e.g., duraluminum), and also comprises an inner insulating layer 16b composed of a non-conductive material (deposited on the inner surface of the outer housing layer 16a via any appropriate process, such as by application of a physical or electrostatic coating, physical vapor deposition, micro-arc oxidation, etc.).

Advantageously the housing 16 of the present invention readily solves one of the most significant challenges in both the design and in fabrication of vacuum-based devices—the need to carefully match the thermo-expansion factors of materials selected for the metal bases (e.g. sockets, pins, etc.) of the device, and of materials for the glass/ceramic vacuum-enveloping housings, and the design limitations of having to work in the very narrow range of thermal expansion values of glass/ceramic materials. The inventive housing 16 does not suffer from the above thermo-expansion matching limitations, and furthermore by virtue of its metal-based composition has much higher thermal conductivity.

Thus, while there have been shown and described and pointed out fundamental novel features of the inventive apparatus as applied to preferred embodiments thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices and methods illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.

Claims

1. A method for fabricating a vacuum enveloping component for use with vacuum-based electronic and thermo-electric devices, comprising the steps of:

(a) fabricating a hollow housing from a material comprising at least one metal of at least a predetermined desired degree of thermal and mechanical stability, said hollow housing being sized and configured to provide vacuum-enveloping functionality to a predetermined vacuum-based device, and comprising an interior surface region, and

(b) depositing an insulating material layer over at least a substantial portion of said inner surface region.