US3704387A

US3704387A - Cathode ray tube target structure supported by the forward portion of the envelope and having a thermal barrier therein

Info

Publication number: US3704387A
Application number: US119146A
Authority: US
Inventors: Mark E Carpenter; Harry E Smithgall
Original assignee: GTE Sylvania Inc
Current assignee: GTE Sylvania Inc
Priority date: 1971-02-26
Filing date: 1971-02-26
Publication date: 1972-11-28
Anticipated expiration: 1989-11-28
Also published as: GB1322302A

Abstract

An improved electrical input-output target structure is provided for a cathode ray tube. This structure, being supported by the forward closure portion of the envelope, comprises an annular first metallic member, a planar target member seated thereon to make peripheral electrical contact therewith, a second metallic member having a planar surface predeterminately spaced from the target member to provide a thermal barrier therebetween, and resilient means oriented peripherally within the barrier space to exert pressure against the target member thereby assuring positive electrical contact between the target and the annular member.

Description

United States Patent Carpenter et al.

[ 51 Nov. 28, 1972 [s41 CATHODE RAY TUBE TARGET STRUCTURE SUPPORTED BY THE FORWARD PORTION OF THE v ENVELOPE AND HAVING A THERMAL BARRIER THEREIN [72] Inventors: Mark E. Carpenter; Harry E.

Smithgall, both of Seneca Falls, NY.

[73] Assignee: GTE Sylvania Incorporated 221 Filed: Feb. 26, 1971 [21] Appl. No.: 119,146

52 U.S. c1. ..313/257, 313/67, 313/89 51 1111.01. .1101, 1/88, l-IOlj 19/42 58 Field of Search ..343/67, 89,257

561 5 References Cited 0 UNITED STATES PATENTS 5,259,774 7/1966 Ney ..313/89 x 3,287,585 11/1966 Randels ..313/s9 2,707,753 5/1955 Marshall ..313/257 ux 3,137,803 6/1964 Ney et a]. ..3l3/67 3,309,552 3/1967 Cairnsetal ..3l3/89 2,493,539 1/1950 Law ..3l3/89 Primary Examiner-David Schonberg Assistant ExaminerToby l-I. Kusmer AttorneyNorman J. OMalley, Donald R. Castle and Frederick H. Rinn ABSTRACT 11 Claims, 4 Drawing Figures PATENTEnnuv 28 I972 3.704.387

INVENTORS. l 4 MARK a. CARPENTER x.

. BY HARRY a. SMITHGALL ATTORNEY PATENTEUnnvee m2 34-704 387 sum 2 0F 2 INVENTORS MARK E.- CARPENTER 8 HARRY a. SMITHGALL ATTOEN EY CATHODE RAY TUBE TARGET STRUCTURE SUPPORTED BY THE FORWARD PORTION OF THE ENVELOPE AND HAVING A THERMAL BARRIER THEREIN BACKGROUND OF THE INVENTION This invention relates to cathode ray tubes and more particularly to animproved electrical input-outputtype of target structure and to a cathode ray tube employing the same.

In certain kinds of cathode ray tubes, not exhibiting a direct view display, as for example those employing an electrical input-output type of target structure, the output therefrom is transferred to and shown on a separate monitor or other suitable display device. The target structures for tubes of this kind are often supported at the forward closure portion of the envelope by supportive and connective leads sealed therein, at least one of which is extended therethrough to provide an external electrical connection for the target. One type of forward closure is made by circumferentially sealing thereto a header or wafer, containing a circular array of leads to which the target structure is attached. Since the target structure is inherently in the proximity of the seal, the heat necessary to consummate the hermetic closure is sometimes of a degree deleterious to the target member. In addition, there have been occasions when the target member becomes slightly loose in the structure. This fosters a vibratory condition which propagates unwanted noise and usually results in a poor electrical connection with the target. It has been noticed that such resultants markedly affect the quality of the operational characteristics of the tube.

OBJECTS AND SUMMARY OF THE INVENTION It is an object of the invention to reduce the aforementioned disadvantages and to provide an improved input-output type of target structure for cathode ray tube utilization. 4

Another object is to provide a cathode ray tube target structure that is less affected by sealing heat.

A further object is to provide an improved target structure wherein positive electrical contact is maintained with the target member.

The foregoing objects are achieved in one aspect of the invention wherein an improved input-output type of target structure comprises an annular first metallic member, a planar target member seated thereon in a manner to make peripheral electrical contact therewith, a second metallic member having a planar surface predeterminately spaced from the planar target member to provide a thermal barrier therebetween, and resilient means oriented peripherally within the barrier space to exert pressure against the target member to assure positive electrical contact between the target and the annular member. The aforedescribed target structure is supported by the forward closure portion of the encompassing envelope.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partially sectioned storage-type cathode ray tube utilizing the invention;

FIG. 2 is a plan view showing a portion of the target structure taken along the line 2-2 of FIG. 1;

FIG. 3 is a partial section of a storage-type tube illustrating another embodiment of the invention; and

FIG. 4 is a perspective further defining the resilient means shown in FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT For a better understanding of the present invention, together with other and further objects, advantages and capabilities thereof, reference is made to the following specification and appended claims in connection with the aforedescribed drawings.

While the improved target structure of the invention relates equally to several types of cathode ray tubes employing generally end-supported electrical inputoutput forms of targets, the exemplary embodiments described herein relate particularly to target structures utilized in storage-type tubes.

With reference to the drawings, there is shown in FIG. 1, a partially sectioned cathode ray tube'll whereof the encompassing envelope 13 has forward and rearward defined

closure portions

15 and 17 respectively.

Positioned within the envelope is a conventional multi-electrode electron gun 19 of which only a portion of the control electrode 21 is shown. An associated substantially planar open-mesh electrode 23, positioned adjacent to the frontal opening of the control electrode 21, is electrically isolated therefrom by an annular insulative ring 25. The electrical connection 27 for the mesh electrode 23 and similar connections for the several other electrodes of the multi-electrode gun 19 are arranged to extend through the rearward closure portion 17 of the envelope 13, being evidenced thereat by a plurality of protruding external lead connections The improved target structure 31 is positioned within the forward portion of the envelope 13 in a manner to receive the controlled electron beam 33. In detail, this structure 31 comprises an annular first metallic member 35 having a peripheral upstanding substan tially cylindrical-type sidewall 39 wherefrom an instanding ledge 41 is integrally formed at one end in a manner to define a central opening 37. This annular member 35 is formed of a metal such as non-magnetic stainless steel and is spatially oriented relative to the mesh electrode 23 with the ledge 41 being adjacent thereto.

A planar target member 43 having first and

second surfaces

45 and 47 respectively, is positioned within the annular member 35 with the peripheral portion of the first surface 45 being seated on the instanding ledge 41 to make electrical contact therewith. Usually the target member 43 includes a substrate with electron sensitive material associated therewith, such material being exposed in substantially the central opening 37. In this instance, the target member 43 comprises a monolithic silicon wafer 49 having disposed on the first surface 45 thereof an electron-retentive sensitive target material 51 in the form of an array of multitudinous minute islands of silicon dioxide. The target structure incorporating this material is capable of storing video information, a characteristic which additionally can be utilized for scan conversion purposes such as required for sending wide bandwidth information over communication lines or converting graphical display information to a raster scanned format.

A circular substantially cup-shaped second metallic member 55, of a material such as non-magnetic stainless steel, is formed to have a planar bottom portion 57 with a peripherally upstanding wall 59 there-around. This cup-shaped member 55 is telescoped within the cylindrical-type sidewall 39 of the annular member 35 to I a position predeterminately removed from the second surface 47 of the target member 43 to provide a thermal barrier or spacing x therebetween, the significance of which willbe described later in this specification. The aforementioned spacing x is maintained by bonding the contiguous wall 59 and sidewall 39 members, such as by a plurality of welds 61 spacedly effected therearound.

Within the spacing x resilient means 63 are peripherally oriented in a partially compressed manner between the bottom of cup-shaped member 55 and the I second surface of the target member. 43 to effect limited contact pressure against the periphery of the target member 43 at a plurality of points therearound thereby assuring positive electrical contact between the target 43 and the instanding supporting ledge 41. With particular reference to FIGS. 1 and 2, in this instance the resilient means 63 comprises a plurality of at least three peripherally oriented bowed leaf-type springs 65. For example, a first end 67 of each spring 65 is affixed, as by welds 69, to the peripheral portion of the planar bottom portion 57 of the second member 55, thereby effecting limited contact of the bowed portion 71 of the spring with the second surface 47 of the target member 43. By this manner, the second end 73 of each spring 65 also makes pressured contact with the bottom of the second member 55.

Attached to the target structure 31 are support and electrical connective means 75. As illustrated in FIG. 1, the target structure is positioned in spaced relationship with the forward closure portion of the tube envelope 13 by a plurality of leads 77, of which three are shown. These leads are spatially affixed to the bonded wall-

sidewall portion

39, 59 of the target structure and are sealed in the forward closure portion, as at 78, to

provide positional support for the target structure. At

peripherally oriented pressure against the target member 43 to assure positive electrical contact with the annular member 35. The wave-type convolutions 83 in the washer provide a plurality of hills-and-

dales

85, 87 which effect the necessary pressure points of limited contact.

FIG. 3 further illustrates another embodiment for supporting the target structure 31 in the forward clo sure portion of the envelope13. A substantially axially oriented lead 89 is fixedly attached 91 to the planar bottom portion 57 of the second member 55 and extended forward therefrom in a manner to be sealed 78 in the forward closure portion 15'. Thus, the axial lead 89 provides both support and electrical connection for the target structure 31.

To describe the importance of the thermal barrier space x, reference is made to FIGS. 1 and 3. To achieve the multiple lead support in the forward closure portion 15, the assembled target structure 31 is usually affixed at a predetermined'height on leads which are priorly sealed in a circular glass wafer or header 95. The target structure 31 and header 95are then positioned relative to the open end of the tube envelope, whereupon a circumferential seal 97, between the periphery of the glass header and the wall of the envelope,'produces the hermetic forward closure portion 15. Since the heat required to effect the circumferential seal 97 is substantial and is in close proximity to the positioned target structure 31, the thermal barrier spacing x advantageously affords protection for the planar target member 43. When the single support and connective lead 89 is utilized, as shown in FIG. 3, the attachment 91 to the planar portion 57 of the second member 55 is made prior to assembly of the target structure. The subsequentally assembled structure 31, with the axial lead 89 attached, is then positioned within a closed end envelope having an axial perforation therein to accommodate the lead 89 inserted therethrough, whereupon a conventional axial seal 97 is consummated. While less heat is required for this limited type of axial seal, a certain amount is directed toward the structure and conducted thereto by the lead 89. Again, the thermal barrier spacing x is beneficial in protecting the target member 43 from the deleterious effects of sealing heat.

As previously mentioned, the resilient means 63 makes effective but limited contact with the periphery of the target member 43 and thereby affords only a minimal path for sealing heat conduction thereto.

Thus, there is provided an improved electrical inputoutput type of target structure for a cathode ray tube. The predetermined protective spacing between the planar portion 57 of the second member and the target wafer 49 provides an advantageous thermal barrier which is particularly beneficial during tube fabrication, and the resilient means peripherally accommodated in the barrier space provides improved and positive electrical contact for the target member thereby enhancing operational characteristicsof the tube.

While there have been shown and described what are at present considered the preferred embodiments of the invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the scope of the invention as defined by the appended claims.

What is claimed is:

1. An improved electrical input-output type of target structure for a cathode ray tube having an electron source positioned to beam electrons to said target oriented in spaced relationship to the forward closure portion of an encompassing envelope and supported by means inwardly extending from said closure portion, said target structure comprising:

an annular first metallic member;

a planar target substrate member having electron sensitive target material associated with one surface thereof, said target member being peripherally seated in said annular member in a manner that said target material makes substantially peripheral electrical contact therewith;

a second metallic member positioned within and peripherally affixed to said annular member, said second member having a planar surface predeterminately spaced from said target member to provide a thermal barrier therebetween; and

resilient means oriented peripherally within said barrier space to exert limited areas of peripheral pressure against said planar surface of said affixed second member and said target substrate member to assure positive electrical contact between said electron sensitive target material and said annular member.

2. The improved target structure according to claim 1 wherein said resilient means effects limited contact pressure against the periphery of said target in at least three substantially equi-spaced points therearound.

3. An improved electrical input-output type of target structure for a cathode ray tube having an electron source positioned to beam electrons to said target oriented in spaced relationship to the forward closure portion of an encompassing envelope and supported by means inwardly extending from said closure portion whereof at least one target connection extends therethrough, said target structure comprising an annular first metallic member defining a central opening and having a peripheral upstanding cylindrical-type sidewall with an instanding ledge integrally formed at one end thereof, said annular member being spatially oriented relative to the forward end of said electron source with said ledge being adjacent thereto;

a planar target substrate member having first and second surfaces with said first surface being electrically conductive and having electron sensitive target material associated therewith, said target member being positioned within said annular member with the peripheral portion of said first surface being seated on said ledge to make electrical contact therewith, said electron sensitive target material being oriented in substantially said central opening;

a circular substantially cup-shaped second metallic member having a planar bottom portion with a peripherally upstanding wall therearound, said cup-shaped member being telescoped within said cylindrical-type sidewall of said annular member to a position predeterminately removed from said second surface of said target member to provide a spacing therebetween, said wall and sidewall being bonded together to maintain said spacing to provide a thermal barrier between the bottom of said cup-shaped member and said target member;

resilient means oriented peripherally within said spacing in a partially compressed manner to effect spaced apart areas of pressure against the periphery of said target member to assure positive electrical contact between said electron sensitive target material and said ledge; and

target support and electrical connective means sealed in and extended through said forward closure portion of said envelope.

4. The improved target structure according to claim 3 wherein said resilient means is formed of at least three peripherally oriented bowed leaf-type springs 6 spatially positioned to effect limited areas of pressure against said target substrate to provide said positive electrical contact between said electron sensitive target material and said ledge.

5. The improved target structure according to claim 4 wherein each of said bowed leaf-type springs has a first end of each spring affixed to the planar bottom portion of said cup-shaped member with the bow of the spring making limited peripheral contact with said target member, a second end of each spring also makes contact with the planar bottom portion of said second member but is unaffixed thereto.

6. The improved target structure according to claim 3 wherein said resilient means is in the form of a resilient wavetype washer circumferentially dimensioned to peripherally fit within said annular member.

7. The improved target structure according to claim 3 wherein said support and connective means are in the form of a plurality of leads spatially affixed to said wallsidewall portion of said structure.

8. The improved target structure according to claim 3 wherein said support and connective means is in the form of a substantially axially oriented lead extending forward from the planar bottom portion of said cupshaped member.

9. An improved target structure according to claim 3 wherein said target is a storage type member comprising a silicon wafer-type substrate having disposed on the first surface thereof a sensitive target material in the form of multitudinous minute islands of silicon dioxide.

10. A storage type cathode ray tube comprising:

an envelope having forward and rearward defined closure portions;

a multi-electrode electron gun structure positioned within said envelope in a manner to direct at least one electron beam toward the forward portion thereof, the electrical connections for said gun being substantially through the rearward closure portion of said envelope;

an improved electrical input-output type of target structure positioned within the forward portion of said envelope to receive said electron beam; said target structure comprising an annular first metallic member, a planar storage target member having electron sensitive material disposed on one surface thereof and seated on said annular member in a manner that said target material makes peripheral electrical contact therewith, a second metallic member positioned within and affixed to said annular member, said second member having a planar surface predeterminately spaced from said target member to provide a thermal barrier therebetween, and resilient means oriented peripherally within said barrier space to exert areas of pressure against said target member to assure positive electrical contact between said electron sensitive target material and said annular member; and

target support and connective means afiixed to said target structure and extending through said forward closure portion of said envelope, said connective means effecting electrical connection with said annular member.

11. A storage type cathode ray tube according to claim 10 wherein the resilient means makes limited contact pressure against said target member in at least three substantially equispaced peripheral points.

Claims

1. An improved electrical input-output type of target structure for a cathode ray tube having an electron source positioned to beam electrons to said target oriented in spaced relationship to the forward closure portion of an encompassing envelope and supported by means inwardly extending from said closure portion, said target structure comprising: an annular first metallic member; a planar target substrate member having electron sensitive target material associated with one surface thereof, said target member being peripherally seated in said annular member in a manner that said target material makes substantially peripheral electrical contact therewith; a second metallic member positioned within and peripherally affixed to said annular member, said second member having a planar surface predeterminately spaced from said target member to provide a thermal barrier therebetween; and resilient means oriented peripherally within said barrier space to exert limited areas of peripheral pressure against said planar surface of said affixed second member and said target substrate member to assure positive electrical contact between said electron sensitive target material and said annular member.

3. An improved electrical input-output type of target structure for a cathode ray tube having an electron source positioned to beam electrons to said target oriented in spaced relationship to the forward closure portion of an encompassing envelope and supported by means inwardly extending from said closure portion whereof at least one target connection extends therethrough, said target structure comprising an annular first metallic member defining a central opening and having a peripheral upstanding cylindrical-type sidewall with an instanding ledge integrally formed at one end thereof, said annular member being spatially oriented relative to the forward end of said electron source with said ledge being adjacent thereto; a planar target substrate member having first and second surfaces with said first surface being electrically conductive and having electron sensitive taRget material associated therewith, said target member being positioned within said annular member with the peripheral portion of said first surface being seated on said ledge to make electrical contact therewith, said electron sensitive target material being oriented in substantially said central opening; a circular substantially cup-shaped second metallic member having a planar bottom portion with a peripherally upstanding wall therearound, said cup-shaped member being telescoped within said cylindrical-type sidewall of said annular member to a position predeterminately removed from said second surface of said target member to provide a spacing therebetween, said wall and sidewall being bonded together to maintain said spacing to provide a thermal barrier between the bottom of said cup-shaped member and said target member; resilient means oriented peripherally within said spacing in a partially compressed manner to effect spaced apart areas of pressure against the periphery of said target member to assure positive electrical contact between said electron sensitive target material and said ledge; and target support and electrical connective means sealed in and extended through said forward closure portion of said envelope.

4. The improved target structure according to claim 3 wherein said resilient means is formed of at least three peripherally oriented bowed leaf-type springs spatially positioned to effect limited areas of pressure against said target substrate to provide said positive electrical contact between said electron sensitive target material and said ledge.

7. The improved target structure according to claim 3 wherein said support and connective means are in the form of a plurality of leads spatially affixed to said wall-sidewall portion of said structure.

8. The improved target structure according to claim 3 wherein said support and connective means is in the form of a substantially axially oriented lead extending forward from the planar bottom portion of said cup-shaped member.

10. A storage type cathode ray tube comprising: an envelope having forward and rearward defined closure portions; a multi-electrode electron gun structure positioned within said envelope in a manner to direct at least one electron beam toward the forward portion thereof, the electrical connections for said gun being substantially through the rearward closure portion of said envelope; an improved electrical input-output type of target structure positioned within the forward portion of said envelope to receive said electron beam; said target structure comprising an annular first metallic member, a planar storage target member having electron sensitive material disposed on one surface thereof and seated on said annular member in a manner that said target material makes peripheral electrical contact therewith, a second metallic member positioned within and affixed to said annular member, said second member having a planar surface predeterminately spaced from said target member to provide a thermal barrier therebetween, and resilient means oriented peripherally within saId barrier space to exert areas of pressure against said target member to assure positive electrical contact between said electron sensitive target material and said annular member; and target support and connective means affixed to said target structure and extending through said forward closure portion of said envelope, said connective means effecting electrical connection with said annular member.