CA2196040A1 - Flat display spacer structure and manufacturing method - Google Patents
Flat display spacer structure and manufacturing methodInfo
- Publication number
- CA2196040A1 CA2196040A1 CA 2196040 CA2196040A CA2196040A1 CA 2196040 A1 CA2196040 A1 CA 2196040A1 CA 2196040 CA2196040 CA 2196040 CA 2196040 A CA2196040 A CA 2196040A CA 2196040 A1 CA2196040 A1 CA 2196040A1
- Authority
- CA
- Canada
- Prior art keywords
- spacer
- anode
- elements
- display panel
- spacer elements
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
- H01J9/24—Manufacture or joining of vessels, leading-in conductors or bases
- H01J9/241—Manufacture or joining of vessels, leading-in conductors or bases the vessel being for a flat panel display
- H01J9/242—Spacers between faceplate and backplate
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
- H01J29/02—Electrodes; Screens; Mounting, supporting, spacing or insulating thereof
- H01J29/028—Mounting or supporting arrangements for flat panel cathode ray tubes, e.g. spacers particularly relating to electrodes
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
- H01J29/86—Vessels; Containers; Vacuum locks
- H01J29/864—Spacers between faceplate and backplate of flat panel cathode ray tubes
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J31/00—Cathode ray tubes; Electron beam tubes
- H01J31/08—Cathode ray tubes; Electron beam tubes having a screen on or from which an image or pattern is formed, picked up, converted, or stored
- H01J31/10—Image or pattern display tubes, i.e. having electrical input and optical output; Flying-spot tubes for scanning purposes
- H01J31/12—Image or pattern display tubes, i.e. having electrical input and optical output; Flying-spot tubes for scanning purposes with luminescent screen
- H01J31/123—Flat display tubes
- H01J31/125—Flat display tubes provided with control means permitting the electron beam to reach selected parts of the screen, e.g. digital selection
- H01J31/127—Flat display tubes provided with control means permitting the electron beam to reach selected parts of the screen, e.g. digital selection using large area or array sources, i.e. essentially a source for each pixel group
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J2329/00—Electron emission display panels, e.g. field emission display panels
- H01J2329/86—Vessels
- H01J2329/8625—Spacing members
- H01J2329/864—Spacing members characterised by the material
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J2329/00—Electron emission display panels, e.g. field emission display panels
- H01J2329/86—Vessels
- H01J2329/8625—Spacing members
- H01J2329/865—Connection of the spacing members to the substrates or electrodes
- H01J2329/866—Adhesives
Abstract
A spacer structure (10) for use in a flat panel display (100), and a corresponding flat panel display article (100) are disclosed, together with an appertaining method of fabricating the spacer structure utilizing a photosensitive precursor material which is selectively irradiated, developed and etchingly processed to produce shaped standoff elements for a unitary spacer structure. The spacer structure may be dimensionally fabricated to precisely align with a selected pixel region, comprising a single pixel or an array of pixels, e.g., a color (red, blue, green) triad.
Description
W0 96/03764 1 ~ u.,,~
~ 1 --FLAT DISPLAY SPACER STRUCTURE AND MANUFACTURING METHOD--DESCRIPTION
Fleld of the l"~_..llon This invention relates generally to flat panel displays coll~ aillg spaced-apartanode and field emitter plates, and more particularly to a flat panel display assembly of such type utilizing novel spacer means.
De~ n of the Related Art In the use of field emitter l~chl)ology, a wide variety of flat panel display asse,",'" have been proposed by the prior art. In general, these display ass~",' ' comprise spaced-apart cathode (emitter) and anode plates, wherein the emitter plate comprises a multiplicity of field emission elements which produce electron beams which are lldll~,,,iLL~d to the anode display plate, which may for example comprise an array of phosphor elements or other lu",i"es~,~"l materials or members, which are lull,i,lesc~,ltly responsive to the i,,,,ui,,ge,,,e,,L of electrons thereon.
In the manufacturing of flat panel display asst:" ' " of the above-discussed type, the respective emitter and anode plates must be readily fabricated in spaced-apart ,~ldlional,;~. to one another, and a variety of spacer means and methods have been proposed in the prior art to effectuate the required spaced-structuralIt:ldliollsl,i~- between the plates.
More ~- ~r- lly, the spacer structure is a critical element in the development of large-area reduced-pressure flat panel displays, which is a practical obstacle to the convergence of other aspects of display It:~:hl lology, such as emitter sources and pho:,,ullu,:,. The use of displays in a wide spectrum of ,, ' ' ls, including defense, scientific, medical, educational, business and r~ dliondl usages, has pl~ ,.dltld, and yet the potential for additional:,, ' " ,s and l~fi"t:",~"l in the conventional It:~,hllulogy is substantial. With the p,.' ~ dliun of devices such as portable work stations, lap tops, palm tops, pen-based pads, video phones, cellular phones, digital high definition television (HDTV), etc., and the prulilt1rdlion of world-wide multimedia networks and satellite direct access --r '"" 1~ the volume of available cyberspace ill~ulllldliull is aldu5Jelillg in amount, and the visual display appears to be the only device which is effectively poised to communicate in a quick and efficient manner the vast amount of available illrullllaLiull to users thereof.
Concerning specific ", " l areas of flat panel displays, ~ ' ls such asportable equipment and miniaturized ,,,i..ruele.,llu,,ic devices require extremely small volume to viewing area ratios, which more generally are desirable in a wide variety of othem,, ' la. Lap top, notebook and pen-based computer devices require flat panel displays to constitute cu"""~,..ial'y viable devices. The current promise of digital HDTV may never be realized in many households if it demands space for a 10û cubic foot cathode ray tube (CRT) or rear-projection based monitor. A truly functional and affordable flat panel display le..h,loloyy is likely to displace virtually every other form of two-di",el)siollal display, including those used in stereo pair gent" 1 for 3-D viewing.
Despite its promise, many ~ u~ ~c l~,,ll"oloyias including liquid crystal displays (LCD's), active matrix liquid crystal displays (AMLCD's), plasma displays, electrolu",i"esce"l displays and vacuum fluorescent displays have been utilized as coll""el.;idl alternatives to flat panels, but all of these " u.ltk/c displaydevices fall far short of providing an optimum flat panel illl~ lllelltdliuil. Major issues such as cost, power efficiency, viewing angle, briul,tl,esa, and color purity diminish their utility, non t~lhele55, the demand for flat panel functionality is sufficiently great so that such serious limitations currently not only are tolerated, but su~-recRf~llly compete with traditional display Lt:~.l),lology.
Field emitter array (FEA) displays provide a new display l~.hnology that is at least Ll,eo~ .al'y capable of meeting all of the requirements for a general purpose flat panel display. Advantages of FL--A display l~ull~uloyy include thinness of the panel (no bulky CRT tube and yoke, or back light, is required), low weight ullala~ liatics, wide viewing angle capability, wide range of color viewing capacity, high efficiency (direct light yelleldlioll~ cold cathode electron source means), high b,i~hl,leaa, high resolution, very fast response time, wide dynamicrange ffrom night levels to direct sunlight visibility), wide l~ ,uel Ire range operating capability, instant turn-on character, back site co,,,,uune,,l mounting ability, and reduced cost (being less expensive and much simpler in structure than the AMLCD).
2~1 96040 ~ 3 Although the art has directed col,aide,dble effort to basic structures, materials, and manufacturing p~ucesses necessary to produce emitters for display purposes, unfortunately the critical spacer structure has not received a significant amount of attention.
Display structures using field emitters require a sufficient distance between the emitter (cathode) and the phosphor plate (anode) to isolate high anode voltages used to achieve the most efflcient excitation of the light-gene,dLi"g phosphOIa.Spacing dil,lerlaiu"a on the order of from about û.5 mm to about 1.5 mm are typical. These spacing .li",el,sior,s, while seemingly small, are in fact very large compared to the mean free path of electrons in dLIIIua~ ulic pressure gases between the respective cathode and anode plates. As a result, the spacing between plates must be evacuated to the pressure levels found in typical CRT's.
Other flat panel display L~-,lllloloyies also require partial (plasma displays) or co",yd,dL,le (vacuum fluorescent displays) levels of evacuation. Evacuation of the space between the cathode and anode plates places a one dLIII0afJIl~l~ (760 mm) static load on the plates and produces a plate deflection that is d~.endel,L o the area, strength and thickness of the material of construction of the plate, typically glass. Excessive deflection may seriously adversely affect the operating ulldla.~L~IibLk,a of the flat panel display, in such respects as pixel size, uniformity of L,iyl,L"es:" and may increase the risk of anode to grid or cathode arcing. For small displays, such deflection is not a problem of significant character, due to the di~ .iulls involved. Typical glass Ll,i.:hl,esses of 2-3 mm may be used in perimeter-supported displays of up to 50 mm and potentially higher dilll~llaiOIls, but for larger area display articles, the corlt:a,uondillg need to increase plate thickness to acco"""o.ldL~ such pressure levels would suuaLd,,'i~ add to the thickness and weight ulldld~iLt:liaLius of the overall display and is not conside,esd P~cepb ~IP or desirable for collllllt:ll,idl and aesthetic reasons. Accordingly, for larger area displays, internal spacer means are necessary to prevent undue deflection with the consequent adverse effects on operability, it being l~coy"i~t:d that excessive pressure deflection in the absence of suitable spacer (support) means in the interior volume of the flat panel display article may result in rupturing of the evacuated plate and loss of its utility for its intended purpose.
The plate spacer structure introduces a number of structural and design cu~,ul~iLies to the ~dbliCdLiUn of the flat panel display article. The spacer stnucture must be strong enough to support the static pressure load, as well as WO 96/03764 2 1 9 6 0 4 0 PcrluS9~l10028 any additional dynamic load resulting from handling, assembly, and use of the display. Further, the spacer structure must be fabricated to fit between pixels or pixel arrays (e.g., triads of color sub-pixels). The spacer structure further must stand off (insulate) the high anode potential. The spacer structure additionallymust provide a continuous open pathway parallel to the plates to allow both initial evacuation of the display panel article, and long-term gettering of slowly released gas cu~ llilldl~ts (off-gassing in situ in the interior volume of the display panel).
From a design sLdlldlJoilll, the spacer structure must permit alignment to the emitter (cathode) pixel structures, as well as to the anode plates phosphor color patterns in color display articles. The spacer structure must also be cost-effective in ~dbliCdLiOn and assembly.
The foregoing requirements present a great challenge in the development of conllller~.i..lly Arre},~ le, mass-producible flat panel display articles that are field emitter-based, and provide medium to large area display capability.
Currently practiced spacing means and methods have r--- ' ' 3C' severe :.hulL..u~ , One fleld emitter display article prototype devised by LETI in France, utilizes glass spheres which are adhered to the emitter plates with a screened-on organic adhesive medium. The spherical spacer elements are ulldesildule because their aspect ratio (1:1) do not satisfy the requirements ofhigher resolution displays and their shape increases the potential for arcing between the anode and the grid or emitters. Organic adhesives also are u~desildule because of the ~c~O~ d high temperature sealing con" ~.,s required, evacuation bake requirements during pump-out, long-term outgassing loads in the small volume static vacuum space, and because the low dielectric constant of the organic adhesive at the interface promotes splash-over.
The use of cured phuLusen ~c polyimide spacer blocks formed directly on the emitter plate from 100 ~;.,Iu~ ,.-thick films has been proposed. This technique also is severely limited in aspect ratio l.ihdldULeli Lil ::- and long-term outgassing properties of the polyimide material in small high vacuum as~e",' ' has not been de" ,u"~L, dled .
Other plasma dispiays have been produced using tall, velLi~.ally standing metal wire segment spacers. The insulated AC operation of these panels allows the use of these metal spacers which are individually placed on an adhesive material, , . , _ _ _ _ _ _ == . . . . _ _ ... _ _ . _ .
WO 96/03764 2 ~ 9 6 0 4 0 PCT/US95/10028 ~ 5 in a standing position but they are u"~ for field emitter displays. The Illaill~.ndllce of spacers in a precise vertical position during the fabricationoperation is a difficult and yield-limiting task. Although collld~ ldliull is less of a problem in plasma display ~F ~s which work in a moderate pressure gas environment, the colltcllllilldliun ;.~ oc;~l~d with the use of such adhesive material with the metal spacers is highly ~",deai,dule in field emitter-based panel article '15.
Accordingly none of the d~u,~",t:"Liol,ed conventional spacer techniques satisfies the req~ ",~"t~ of high pe,ru""d"~.e vacuum panel displays.
It therefore is an object of the present invention to provide a means and method of spacing emitter and anode plates in a field emitter-based flat panel display assembly, which overcomes the L'u,~",~"t;oned various disadvantages of the prior art spacer means and methods.
it is another object of the present invention to provide such improved spacer means and method which are effectively utilized in large area display panel ~i~ ns.
It is a further object of the present invention to provide such improved spacer means and method which are non-deleterious to the pixel a"d"~",~"l and operation of the display panel.
Other objects and advantages of the present invention will be more fully apparent from the ensuing disclosure and appended claims.
~RY OF THE INVENTION
In one aspect, the present invention relates to a display panel cu~utiai~g an anode plate, an electron source plate co",,u,i:,i"g an array of field emitter elements defining with the anode plate pixels of the display panel, with the anode plate and electron source plate being ",c.i"td;"ed in spaced l~ldlioll:~hiu to one another by spacing means co~ JIiaillg a unitary spacer structure cor"urisi"g pllutufv~ ed spacer elements joined to a support structure and i" uosed in bearing and supporting ~tlldliullshiu between said anode and electron source plates. As used herein, the term ul,utulu"" means that a material is formed by irradiation of a precursor workpiece and then processed to form a structural member or cu",uone"t.
The pl,uLuru,~,,ed spacer elements preferably are constructed and arranged in arrays to circu" lacliLJil Iyly bound a pixel region, e.g., cu",~u, iail ,9 a single pixel, or an array of pixels.
The spacer structure may suitably comprise a support matrix of perpendicularly arranged arrays of elements forming a grid-structure having the spacer elements joined thereto.
Preferably, the spacer elements in the spacer structure comprise columnar elements extending upwardly from the grid support structure.
The unitary spacer structure advantageously is formed, developed, and etched to yield an array of vertically upwardly extending spacer elements extending from and integral with a support grid structure having the spacer elements arranged to bound openings ac-;or"",ocklli"g pu:~it;urlillg in relation to pixel regions forthroughput of electrons from the electron source plate through the spacer structure to the anode plate.
The unitary spacer structure for example may be formed of a developed and etched glass material co,,,,u,i:,i,,g the ,chutufulllled spacer elements.
Co,,t~polldi,,~u,ly, the anode plate may comprise an anode plate substrate metalized with a reflective/conductive metal anode layer of patterned character defining non-metalized openings surrounded by metalized regions of the metalized anode layer, wherein the spacer elements are aligned with the non-metalized openings in the metalized anode layer.
In another aspect, the present invention relates to a method of making a displaypanel cu~,uliai''g an anode plate, an electron source plate including an array of field emitter elements, and a spacer structure including a plurality of spacer elements, i"lt:"uosed between the anode and electron source plates, cor",uriai"ythe steps of:
providing a pllutuae"aili"e material workpiece as a precursor structure of at least a portion of the spacer structure culll,uliainy the spacer elements;
,, , . ... .. = . _ . _ . . , , _ WO 96/03764 2 1 9 6 0 4 0 PCT/US95/lOOU
~ 7 exposing a surface of the phulusenailive material workpiece to phuLusellaili~ lyeffective radiation for sufficient time and at sufficient intensity to phulosenaili~e selected portions of the phutùst:,,ailive material ~.J,hpi~ce, removing non-ph.~ ,osed material from said workpiece to yield at least a portion of the spacer structure including a plurality of spacer elements; and osi"g the spacer structure between the anode and electron source plates, such that the anode and electron source plates are ",d;"ld;"ed in spaced-apart liu~ lahi~J to one another by the spacer structure.
Other aspects, features, and e",bodi",e"ta of the invention will be more fully apparent from the ensuing disclosure and appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a top plan view of a spacer structure according to one e",bo.li",t:"l of the present invention.
Figure 2 is a front elevation view of the Figure 1 spacer structure.
Figure 3 is a bottom plan view of the spacer structure of Fj9UrQ 1.
Flgure 4 is a top plan view of a portion of a field emitter flat panel display assembly, ~,or"~.,iai"a a spacer structure according to one ~",bodi",el,l of thepresent invention, of the type shown in Figure 1, shown superposed on a field emitter color triad array.
Figure 5 is a pe,a~.e~ c view of a flat panel display assembly according to one c:"lbodi"~e"l of the present invention, and featuring spacer structure in au~o,.ld"ce with the invention in an exemplary e:lllbOdi~ lll thereof.
~ Figure 6 is a sectional elevation view of a portion of a flat panel display assembly according to Figure 5, showing the Culll,udllc~llL structure thereof including the emitter and anode plates and spacer structure.
WO 96/0376~ 2 1 9 6 0 4 0 PCT/US95/10028 Figure 7 is a schematic illustration of a process system for photo developing a plluluaellaiIi\le material to form a conical mask region in a substrate.
Figure 8 is a schematic depiction of the conical element formed from the irradiated substrate shown in Figure 7 subsequent to etch removal of phul ~g.osed portions of the substrate.
Figure 9 is a schematic illustration of a process system for irradiating a plluluse~siIi~/e substrate to produce a masked inverted fn,aluco,,iL.c,l region.
Figure 10 is a s- I~c~"~aIic depiction of an inverted fru~tucu"i.al structural element formed by etch removal of irradiated portions of the substrate of Figure 9.
DET~ Fn l:~ESCRIPTION OF THE INVFNTION . AND PREFERRFn ~a~ODlMFNTS THEREOF
The present invention utilizes pllutusellaili~/e materials such as glasses polymers, etc. that can be irradiated, thermally developed and ,he",ica:j etched into complex patterns. The phulus~siIive material may for example comprise a phutusel,sili~/e glass ceramic glass-ceramic material or polymeric material of suitable character. Advantageous glass and ceramic (glass-ceramic) materials suitable for usage include the materials co"""~ y available from Corning Inc.
under the I,~de",~,ks ~ FORM~ and FOTOCERAM~. A particuiarly preferred illustrative material of such type is Fvtulullll~) UV-sensitive glass (Corning Inc.
Corning NY). Such material can provide aspect ratios of up to 4û:1 (aspect ratios as used herein referring to the length or longitudinal dimension of a structure relative to its width or transverse di",el1~iun)~ as well as high quality insulating properties and a."en ~y to forming multilevel structures allowing transverse pathways. Although such materials have inherent potential . ' ~ 'i 1 to use in spacer structures the prior art has not seriously cùllaklelt:d same for flat panel display l~u~ic.lt;on because of their excessive cost and limited size (for example the ~lu,~",~"lioned Fotoform glass is currently available only in 7 x 7 inch maximum sizes.
Accordingly the present invention utilizes such radiation-alterable materials in a novel spacer structure which beneficially utilizes the desirable aspects of .~ 9 materials such as the d~u,~",e"Lioned phulu~u,,,,~ble glass materials, while overcoming their limitations of size and cost.
Accordingly, in a preferred aspect, the present invention cûlltulll,uldl~s the use of relatively small, discreet spacer members, such as is shown in Figure 1.
Figure 1 is a top plan view of a spacer structure 10 in which such spacer member cu",,ur;aes a regular array of standoffs 12, which are vertically upwardly extending elements having upper bearing services 20 for abutting supportive contact with a plate member of a display panel, or such contact with a cc."t::"uondi.,9 opposedly facing spacer structure (i.e., wherein respective facing spacer structures are mated in abutted contact with one another, with for example, one spacer structure being r--- ~ ~ ' with the emitter (cathode) plate of the display panel, and the other spacer structure being ~ ' 3C' with the anode plate of the display article).
The standoffs 12 in this e,,lLu-li,,lt:lll are of truncated pyramidal shape. It will be It:uoylli~t:d that the standoff elements of the support structure may be of any suitable shape or geometry, as necessary or desirable in a given end use ~FF'- - 1.
The standoff elements 20 are i" -uu, " ,eulud in a matrix structure by means of the horizontal support members 14 and the vertical support members 16 (such horizontal and vertical directions referring to the O~ utdt;ull of the spacer structure as shown in Figure 1, it being It:coyll;~:d that the shape of these members and their ul;t:llLdl;ùl1s may be widely varied within the broad practice of the present invention; in general, however, perpendicular and rectangular (square) ~e~ldl;ùnsl~;,us between the members are desirable, for ease of alignment and olitlllldliun relative to the pixels defined by the emitter and anode plates, ashe,~i, Idll~l more fully described.
The standoff elements 20 and the support members 14 and 16 may be integrally formed from a singie block or other form of precursor material. Alternatively, the standoff elements 20 may be separately formed and affixed or secured to the grid~ or matrix formed by support members 14 and 16. In any event, the standoff elements and support members cooperatively formed a unitary support structure which is i,,~u.,uusable between plates or other structural portions of a displaypanel to contribute strength and ",eul,a"iudl integrity to the display article, and to WO 9610376~ 2 1 9 6 0 4 0 PCT/US95110028 permit the display to be evacuated to low vacuum levels without undue static load or, in use dynamic load dt:~icie~ s in the structure and operation of the display panel article.
Fig ure 2 is an elevation view of the spacer structure 10 and Fig ure 3 is a bottom plan view of such spacer structure wherein all parts and features of the structure are col,t,auollui"yly numbered with respect to Figure 1.
The number of "cells" or repeating units in a spacer strurture such as is shown in Figure 1 (such cells referring to the portion of the structure surrounding a given open area 1 8 in the structure) will be d~ ll,i,led by the material and construction, its strength and the frequency of pld~ elll~llt (i.e. number of spacer segments per unit area of the display panel). These spacer structure segments can be individually placed at an d~J~JIu,~ddl~ density across display panels of very large size.
In practice, the spacer structure segments of the type shown in Figures 1-3 may be i,lt~,uosed between respective emitter and anode plates of the display article, in continuous fashion with the spacer segments being contiguous to one another across the full areal extent of the display panel. /'~' u~..iicly the spacer segments may be disposed in spaced-apart l~:ldliullslli,u to one another across such areal extent of the display panel interior volume. The specific dlldllgt:lllelll spacing, size of the spacer segment and frequency may be readily dult:""i"ed without undue exu~lilll~llldliuo by those of ordinary skill in the art based on dt~ ll,,iudliùns of static and dynamic loads and deflection levels of the platesutilized in a given display panel with and without support by the spacer structure.
Fig ure 4 is a top plan view of the spacer structure 10 shown in Fig ures 1 -3 (and whose co""~ont:"l elements are cullt::,,uulldi,l~'y numbered with respect to Figures 1-3) poailioned on a matching field emitter color triad array coi"u,i~i"g a multiplicity of red color elements 26, green color elements 28, and blue colorelements 30, each of said color element triplets (red, green blue) constituting a pixel of the overall array.
This Figure 4 e",bodi",c:lll illustrates the manner in which spacer "en:,iolls can be Illd7~ d and aspect ratios of the support structure reduced by the dlldn~ lll of the emitter color sub-fields within the pixel. The need to stand up an individual high aspect ratio spacer element is eliminated by making the spacer structure segment large enough to cover many pixels, thereby making the aspect ratio of the spacer structure segment relatively small. The spacer structure segment is readily handled and requires no greater alignment control than any other discreetly posilivned element utilized in the display article.
The fine resolution and high aspect ratio capability of the preferred phuLu~u~ dl)le glass material allows the creation of an open structure for both electron passage and lateral gas evacuation within the support structure segment. Concerns about matching of coefficients of exlJallaion are also minimized, since any t~ Jdll:.iVn mismatch is accumulated over only the length of the spacer structure segment and not over the entire length of the display article. The clusters of supports in the spacer structure segment provide greater bearing and racking strength than do isolated individually placed spacer elements, and afford the potential for greatly reducing the number of spacer elements requiring pldc~",elll in the interior volume of the display panel, as dut~,,llliut:d on a unit area of display basis.
The provision of the spacer structure segment of the type illustratively described he,~:.,aboic likewise serves to minimize costs. The small size of the spacer structure segment allows hundreds or even thousands of segments to be fabricated from a plate of precursor (raw) material. The design and divergent exposure process he,t:i"drlt:r more fully described allows complex three-di,,,en:.iu,,al stnuctures of the spacer structure segment to be fabricated with a single exposure which: ' lI;lldlt:S mask ~, ""t:"ts and reduces both processing and mask costs.
Further, the repetitive pattern of the spacer structure segment allows many types of damaged segments (standoff elements) such as those with missins corners, to be employed as long as the remaining spacer structure meets minimum load requirements. Thus, the spacer structure segment tolerates mechanical il,,~.e,r~.,t;vn in the standoff elements and enhances the yield character of the ~dbli " n process, particularly in the instance where the standoff elements are subjected to impact, abrasion, and other forces incident to manufacture and handling which may result in localized i~pe~ ,tivlls in the bearing surfaces of the standoff elements.
The spacer structure of the present invention also has benefits in respect of flashover (arcing) control. Flashover control is of special concern in the rdLIil;dlivn and operation of flat panel field emitter displays because the small spacings clldl d~ ri:~lic of the structure encourage its occurrence. As a countervailing coll:,ideldlioll it is desirable to use as high an anode potential as possible in order to improve efficiency and bl iyl ,I"ess beyond the levels achievable at larger spacing di",t~ iulls. The spacer structures of the present invention are amenable to a, ' ~ ~ of coatings to selected surfaces or portions thereof which enhance high voltage operation while reducing the tendency of the spacer structure to flashover.
Maximum anode potential in operation of the flat panel display is principally governed by the tendency of charge to suddenly and violently travel across the spacer surface as the ~iu~ enliuned flashover pheno",elloll. Flashover generally occurs when the surface charge on the spacer is contiguous enough to fomn an initiating conductive pathway rather than as a result of the spacer structure's bulk insulator properties or defects. The maximum potential therefore is generaliy defined by the absence of flashover. Surface llc:dtlllt~ may be employed to minimize surface charge while electron bu",L,d,d",e"l (due to normaloperation) generally reduces the maximum potential by i"- ,~a:ii"g surface charge.
Figure 5 is a perspective view of aflat panel display 100 colll,uliaillg spaced-apart anode plate 102 and cathode plate 104 of a general type in which the spacer structure of the present invention may advantageously be employed.
Figure 6 is a sectional elevation view of a flat panel display according to one embodiment of the invention. The display panel 205 comprises a bottom plate 206 which may be formed of glass or other suitable material, on the top surface which is provided a series of emitters 207 wherein the emitter cc"",e.:tions areoriented perpendicular to the plane of the drawing page. The emitters 207 are provided with gate row cu,,,,e-liùlls 208, and gate lines 210. The emitters are constnucted over a vertically conducting resistor layer on the substrate. The panel 205 comprises a top plate 212 of a suitable material such as glass. The top plate is ",di"L:.,ed in spaced ItlldLio~ J to the bottom plate by means of spacer elements 213 which feature a flashover control coating 214 on their surfaces exposed to vacuum space 215.
The spacers at the sides of the display may be sealed to the r-- ~ ' d plates bymeans of frits 216 which may for example comprise silica as their material of construction. The top plate 212 may be coated on rts lower surface with a black W096/03764 21 9 6 0 4 0 PCTlUS95/lQ028 ~ 13 matrix material, such as a mixture of barium and titanium, and the RGB phosphors217 are disposed on the top plate against the black matrix material 218. The RGB pl lo~ u,a may optionally be coated with a thin aluminum coating, and may be provided with an IT0 underlayer.
The emitters shown in the panel alldny~",~"l of Figure 6 may alternatively be organized in llwl)o~ llle displays, light panels, sequenceable light strips, andother configurations.
Figures 7-10 illustrate the ~dbl; " I of a spacer structure according to a preferred e",i odi",e"l of the invention.
As shown in Figure 7, a divergent light source 40 is arranged in lightLldll:,lllission l~ldlional,i~, to precursor block 42 formed of a phuluse~silivematerial, such asthe ' ~ el~;u~ed Fotoform glass collllllt:ll,ia"y available from Corning, Inc. (Corning, NY). The light source 40 is selected to emit divergent light beams 46 of a selected suitable wavelength and intensity. The upper (illl~Jillg~ L) surface of the precursor block 42 is masked over a selected area48 by means of masked element 44.
Bysuch d~dngell,~,~t~ the divergent radiation 46 is impinged on surface 49 and into the interior of the precursor block glass material 42. The mask 44 is disposed in relation to the divergent radiation 46 so that the surface region 48 is masked and the radiation path co"t:spu"d;"~ly forms an u"exposecl 42 conical portion of the precursor block 42, with the remainder of the block being pl,~ ,pose~l Thus, the divergent light source produces a controlled degree of exposure under the mask which is d~Jendelll on the distance from the mask or the image plane in the case of projection printing. When mask features are narrow in di~enaions, the light from both sides of the mask crosses within th body of the material, and when developed and etched, results in an illlt~lllledidlt:
height feature. The edges of larger mask features do not meet within the body ofthe precursor block material and therefore result in full height features. In spacer structure segments, height control in the illlt~lllledidl~ structures is non-critical.
The phutu~,~posed precursor block 42 then is baked and fiood exposed to a suitable etchant for the material construction of the precursor block. In such manner, the ~hut ~pùsed portion 52 of the block as shown in Figure 8 is W O 96103764 ~ 2 1 9 6 0 4 0 PC~rN S9S/10028 etchingly removed, yielding the conical-shaped element 50 as a shortened structure in relation to the height or thickness dimension of the precursor block.
Figures 9 and 10 show an analogous process, utilizing a wider mask, to produce a truncated inverted conical shape from the precursor block. In Figure 9, the divergent light source 60 is shown as producing divergent light beams 6 6which impinge on the surface 69 which is partially masked by mask element 64 to provide an u,,t,xposed surface portion 68 on the precursor block 62. The pl,u~ l.osllre is conducted to cw~ lion. The precursor block after phut~ Ypo.~llre then is baked at suitable elevated temperature to develop the phhI ~Q~posed portions of the precursor block, following which the block is subjected to flood exposure of suitable etchant. The etching removes portion 7 2of the precursor block as shown in Figure 10 (wherein the dashed outline denotes the original bounding surfaces of the precursor block 62 (See Figure 9)), yielding the inverted frualu.,o"ical shape of the standoff element 70.
In general, a wide variety of phutusel,aili,le materials may be utilized in the production of spacer structures in acco,dal1ce with the present invention. In the typical process flow, the phutuaell,it;~le material exposed to suitable radiation, e.g., visible or collimated UV light, while selected areas of the phulusensilivematerial workpiece are masked. The ph..~ )osed image then is developed, typically under elevated temperature or other development conditions, followed by optional further development steps including flood exposure in which clear areas of the previously irradiated workpiece are exposed to u" ", ' UV or other radiation without a mask, followed by etch or other removal of the non-masked areas of the workpiece. For example, in the case of a phulusensiti\/e glass material, the unmasked areas of the workpiece may be dissolved in a suitable etchant or reagent medium, such as dilute hydrofluoric acid. Finally, the resulting structural article may be subjected to selected post-treatment ope"~lions such as C~ldlll' ' ' n and/or heat treatment.
Co",,ua,iaon of Figures 8 and 10 shows that the size and shape of the support structure elements may be widely varied by the simple expedient of varying mask size with respect to the resultingly produced shaped member. The technique illustratively described with reference to Figures 7-10 may be employed to produce discreet standoff elements which, as previously described, can be structurally coupled to or secured to other structural elements, e.g., the grid-like matrix of the support structure 10 shown in Figures 1-4. Alternatively, the ~ 15 precursor block utilized to form the standoff elements may be selectively irradiated by suitable masking members to produce a unitary, integral support structure, such as the unitary support structure segment shown in Figures 1-4 hereof.
The anode plate of the flat panel display article of the present invention may be formed and constructed in any suitable manner, within the skill of the art. In apreferred aspect, such anode plate may be aluminized with a reflective/
conductive aluminum anode layer on the surface of a plate of suitable material construction, such as glass. This It:ileuii-~i,uu~ductive aluminum anode layer may suitably be patterned so as to minimize the electric field directly across the spacer structure and to provide an anode ccr",e.,liol1 point. The patterning colll~Jliaes aluminized regions on the anode plate substrate member, and non-aluminized openings defined by the circumscribing aluminized regions. The non-aluminized openings pass and trap incident light more effectively than a black matrix, thereby improving sunlight ,~ of the flat panel dispiay (although a black matrix coating such as titanium or carbon may still be used with such patterned aluminized layer). Such patterned aluminizing of the anode substrate member also reduces the potential for culltdlllilldlion of the interior volume of the flat panel display as a result of the spacer structure p~ujt:utio~ crushing particles or films on the anode surface, or otherwise removing particulate or otherwise removing particulate or finely divided metal or other material which can severely adversely affect the operability of the flat panel display article.
The spacer structure of the present invention may be utilized with surface coatings of various suitable types, which may for example provide enhanced structural or ",ecl1d"i.ial integrity to the spacer structure or otherwise improve its operating (electrical) properties. For example, surface coatings on the spacer structure of slightly leaky insulators may be used to control charging and surface charge accumulation. Examples of such surface coatings include aluminum silicate, alumina, and boron. In such respect, ,uhutusellailive glasses such as the FotoformT~ glass may have very effective surface leakage clldldultlli~ ,s per se as suitable for various ~ a.
.
H will be l~co~u"i~t:d that the phuLufulllli,lg process may be widely varied, asregards the precursor block materials of construction, radiation intensity and wavelength ~hdld~l~liaLil~s, coherency .,I,d,d~,L~riaLics of the radiation, use of other than visible light radiation, e.g., ultraviolet or other actinic radiation, variation in mask size, shape and plact:",e"L, variation in development (e.g., baking WO 96/03764 2 1 9 6 0 4 0 PCT~S9~/10028 conditions) subsequent to initial radiation exposure, and variation in etching reagents and etch conditions, etching here being broadly construed to include any sol~ Ih~ ti~ln process by means of which material is removed from a precursor workpiece sl~hseq~ent to radiation exposure and development.
As an alternative to etching removal of material from photodeveloped v.ol h,uieces, it is within the purview of the present invention to utilize non-etching removaltechniques, including Ille.,l,a"icdl removal processes and procedures, either for bulk removal of material, or for finishing of rough-formed support structures.
In respect of electrical clldldulc~ dtiull and o,ut;"~i~dlion of support structures within the broad purview of the present invention, the testing and o,uLi,,,i~dLion may be carried out in a manner within the skill of the art. For example, electrical testing may be carried out by pldcellle:llL of spacer structures between conductive surfaces onto plates, with the imposition of a variable potential difference across the spacer structure. Leakage occurrence then can be measured together with the occurrence and frequency of flashover events. The cathode plate may in such testing comprise a field emitter array, positioned relative to the spacer structure so that pixels in known positions may be selectively activated, for purposes of measurement while the activated pixels are conducting. By use of different pitches for pixel and spacer co""~on~"L~, pixels with different ,UlUAillliti~s to the spacer structure can be activated without breaking vacuum conditions, or otherwise changing empirical conditions, to thereby test the spacer structure's sensitivity to pixel alignment.
While the invention has been illustratively described with respect to specific preferred features, aspects, and elllL)odi,lld,lt~, it will be ,t:coy"i~ed that the invention may be widely varied, and that numerous other variations"" ' ' ls and alternative elllLJodi",~llt:, are possible, within the spirit and scope of the present invention.
INDUSTRIAL APPLICABILITY
The flat panel displays of the invention have utility in a wide spectrum of f p,B- ~- )5, including defense, scientific, medical, educational, business and rdul~ ~- nal usages, in device ~ ns such as portable work stations, lap tops, palm tops, pen-based pads, video phones, cellular phones, digital high definition television (HDTV), and the like.
.....
~ 1 --FLAT DISPLAY SPACER STRUCTURE AND MANUFACTURING METHOD--DESCRIPTION
Fleld of the l"~_..llon This invention relates generally to flat panel displays coll~ aillg spaced-apartanode and field emitter plates, and more particularly to a flat panel display assembly of such type utilizing novel spacer means.
De~ n of the Related Art In the use of field emitter l~chl)ology, a wide variety of flat panel display asse,",'" have been proposed by the prior art. In general, these display ass~",' ' comprise spaced-apart cathode (emitter) and anode plates, wherein the emitter plate comprises a multiplicity of field emission elements which produce electron beams which are lldll~,,,iLL~d to the anode display plate, which may for example comprise an array of phosphor elements or other lu",i"es~,~"l materials or members, which are lull,i,lesc~,ltly responsive to the i,,,,ui,,ge,,,e,,L of electrons thereon.
In the manufacturing of flat panel display asst:" ' " of the above-discussed type, the respective emitter and anode plates must be readily fabricated in spaced-apart ,~ldlional,;~. to one another, and a variety of spacer means and methods have been proposed in the prior art to effectuate the required spaced-structuralIt:ldliollsl,i~- between the plates.
More ~- ~r- lly, the spacer structure is a critical element in the development of large-area reduced-pressure flat panel displays, which is a practical obstacle to the convergence of other aspects of display It:~:hl lology, such as emitter sources and pho:,,ullu,:,. The use of displays in a wide spectrum of ,, ' ' ls, including defense, scientific, medical, educational, business and r~ dliondl usages, has pl~ ,.dltld, and yet the potential for additional:,, ' " ,s and l~fi"t:",~"l in the conventional It:~,hllulogy is substantial. With the p,.' ~ dliun of devices such as portable work stations, lap tops, palm tops, pen-based pads, video phones, cellular phones, digital high definition television (HDTV), etc., and the prulilt1rdlion of world-wide multimedia networks and satellite direct access --r '"" 1~ the volume of available cyberspace ill~ulllldliull is aldu5Jelillg in amount, and the visual display appears to be the only device which is effectively poised to communicate in a quick and efficient manner the vast amount of available illrullllaLiull to users thereof.
Concerning specific ", " l areas of flat panel displays, ~ ' ls such asportable equipment and miniaturized ,,,i..ruele.,llu,,ic devices require extremely small volume to viewing area ratios, which more generally are desirable in a wide variety of othem,, ' la. Lap top, notebook and pen-based computer devices require flat panel displays to constitute cu"""~,..ial'y viable devices. The current promise of digital HDTV may never be realized in many households if it demands space for a 10û cubic foot cathode ray tube (CRT) or rear-projection based monitor. A truly functional and affordable flat panel display le..h,loloyy is likely to displace virtually every other form of two-di",el)siollal display, including those used in stereo pair gent" 1 for 3-D viewing.
Despite its promise, many ~ u~ ~c l~,,ll"oloyias including liquid crystal displays (LCD's), active matrix liquid crystal displays (AMLCD's), plasma displays, electrolu",i"esce"l displays and vacuum fluorescent displays have been utilized as coll""el.;idl alternatives to flat panels, but all of these " u.ltk/c displaydevices fall far short of providing an optimum flat panel illl~ lllelltdliuil. Major issues such as cost, power efficiency, viewing angle, briul,tl,esa, and color purity diminish their utility, non t~lhele55, the demand for flat panel functionality is sufficiently great so that such serious limitations currently not only are tolerated, but su~-recRf~llly compete with traditional display Lt:~.l),lology.
Field emitter array (FEA) displays provide a new display l~.hnology that is at least Ll,eo~ .al'y capable of meeting all of the requirements for a general purpose flat panel display. Advantages of FL--A display l~ull~uloyy include thinness of the panel (no bulky CRT tube and yoke, or back light, is required), low weight ullala~ liatics, wide viewing angle capability, wide range of color viewing capacity, high efficiency (direct light yelleldlioll~ cold cathode electron source means), high b,i~hl,leaa, high resolution, very fast response time, wide dynamicrange ffrom night levels to direct sunlight visibility), wide l~ ,uel Ire range operating capability, instant turn-on character, back site co,,,,uune,,l mounting ability, and reduced cost (being less expensive and much simpler in structure than the AMLCD).
2~1 96040 ~ 3 Although the art has directed col,aide,dble effort to basic structures, materials, and manufacturing p~ucesses necessary to produce emitters for display purposes, unfortunately the critical spacer structure has not received a significant amount of attention.
Display structures using field emitters require a sufficient distance between the emitter (cathode) and the phosphor plate (anode) to isolate high anode voltages used to achieve the most efflcient excitation of the light-gene,dLi"g phosphOIa.Spacing dil,lerlaiu"a on the order of from about û.5 mm to about 1.5 mm are typical. These spacing .li",el,sior,s, while seemingly small, are in fact very large compared to the mean free path of electrons in dLIIIua~ ulic pressure gases between the respective cathode and anode plates. As a result, the spacing between plates must be evacuated to the pressure levels found in typical CRT's.
Other flat panel display L~-,lllloloyies also require partial (plasma displays) or co",yd,dL,le (vacuum fluorescent displays) levels of evacuation. Evacuation of the space between the cathode and anode plates places a one dLIII0afJIl~l~ (760 mm) static load on the plates and produces a plate deflection that is d~.endel,L o the area, strength and thickness of the material of construction of the plate, typically glass. Excessive deflection may seriously adversely affect the operating ulldla.~L~IibLk,a of the flat panel display, in such respects as pixel size, uniformity of L,iyl,L"es:" and may increase the risk of anode to grid or cathode arcing. For small displays, such deflection is not a problem of significant character, due to the di~ .iulls involved. Typical glass Ll,i.:hl,esses of 2-3 mm may be used in perimeter-supported displays of up to 50 mm and potentially higher dilll~llaiOIls, but for larger area display articles, the corlt:a,uondillg need to increase plate thickness to acco"""o.ldL~ such pressure levels would suuaLd,,'i~ add to the thickness and weight ulldld~iLt:liaLius of the overall display and is not conside,esd P~cepb ~IP or desirable for collllllt:ll,idl and aesthetic reasons. Accordingly, for larger area displays, internal spacer means are necessary to prevent undue deflection with the consequent adverse effects on operability, it being l~coy"i~t:d that excessive pressure deflection in the absence of suitable spacer (support) means in the interior volume of the flat panel display article may result in rupturing of the evacuated plate and loss of its utility for its intended purpose.
The plate spacer structure introduces a number of structural and design cu~,ul~iLies to the ~dbliCdLiUn of the flat panel display article. The spacer stnucture must be strong enough to support the static pressure load, as well as WO 96/03764 2 1 9 6 0 4 0 PcrluS9~l10028 any additional dynamic load resulting from handling, assembly, and use of the display. Further, the spacer structure must be fabricated to fit between pixels or pixel arrays (e.g., triads of color sub-pixels). The spacer structure further must stand off (insulate) the high anode potential. The spacer structure additionallymust provide a continuous open pathway parallel to the plates to allow both initial evacuation of the display panel article, and long-term gettering of slowly released gas cu~ llilldl~ts (off-gassing in situ in the interior volume of the display panel).
From a design sLdlldlJoilll, the spacer structure must permit alignment to the emitter (cathode) pixel structures, as well as to the anode plates phosphor color patterns in color display articles. The spacer structure must also be cost-effective in ~dbliCdLiOn and assembly.
The foregoing requirements present a great challenge in the development of conllller~.i..lly Arre},~ le, mass-producible flat panel display articles that are field emitter-based, and provide medium to large area display capability.
Currently practiced spacing means and methods have r--- ' ' 3C' severe :.hulL..u~ , One fleld emitter display article prototype devised by LETI in France, utilizes glass spheres which are adhered to the emitter plates with a screened-on organic adhesive medium. The spherical spacer elements are ulldesildule because their aspect ratio (1:1) do not satisfy the requirements ofhigher resolution displays and their shape increases the potential for arcing between the anode and the grid or emitters. Organic adhesives also are u~desildule because of the ~c~O~ d high temperature sealing con" ~.,s required, evacuation bake requirements during pump-out, long-term outgassing loads in the small volume static vacuum space, and because the low dielectric constant of the organic adhesive at the interface promotes splash-over.
The use of cured phuLusen ~c polyimide spacer blocks formed directly on the emitter plate from 100 ~;.,Iu~ ,.-thick films has been proposed. This technique also is severely limited in aspect ratio l.ihdldULeli Lil ::- and long-term outgassing properties of the polyimide material in small high vacuum as~e",' ' has not been de" ,u"~L, dled .
Other plasma dispiays have been produced using tall, velLi~.ally standing metal wire segment spacers. The insulated AC operation of these panels allows the use of these metal spacers which are individually placed on an adhesive material, , . , _ _ _ _ _ _ == . . . . _ _ ... _ _ . _ .
WO 96/03764 2 ~ 9 6 0 4 0 PCT/US95/10028 ~ 5 in a standing position but they are u"~ for field emitter displays. The Illaill~.ndllce of spacers in a precise vertical position during the fabricationoperation is a difficult and yield-limiting task. Although collld~ ldliull is less of a problem in plasma display ~F ~s which work in a moderate pressure gas environment, the colltcllllilldliun ;.~ oc;~l~d with the use of such adhesive material with the metal spacers is highly ~",deai,dule in field emitter-based panel article '15.
Accordingly none of the d~u,~",t:"Liol,ed conventional spacer techniques satisfies the req~ ",~"t~ of high pe,ru""d"~.e vacuum panel displays.
It therefore is an object of the present invention to provide a means and method of spacing emitter and anode plates in a field emitter-based flat panel display assembly, which overcomes the L'u,~",~"t;oned various disadvantages of the prior art spacer means and methods.
it is another object of the present invention to provide such improved spacer means and method which are effectively utilized in large area display panel ~i~ ns.
It is a further object of the present invention to provide such improved spacer means and method which are non-deleterious to the pixel a"d"~",~"l and operation of the display panel.
Other objects and advantages of the present invention will be more fully apparent from the ensuing disclosure and appended claims.
~RY OF THE INVENTION
In one aspect, the present invention relates to a display panel cu~utiai~g an anode plate, an electron source plate co",,u,i:,i"g an array of field emitter elements defining with the anode plate pixels of the display panel, with the anode plate and electron source plate being ",c.i"td;"ed in spaced l~ldlioll:~hiu to one another by spacing means co~ JIiaillg a unitary spacer structure cor"urisi"g pllutufv~ ed spacer elements joined to a support structure and i" uosed in bearing and supporting ~tlldliullshiu between said anode and electron source plates. As used herein, the term ul,utulu"" means that a material is formed by irradiation of a precursor workpiece and then processed to form a structural member or cu",uone"t.
The pl,uLuru,~,,ed spacer elements preferably are constructed and arranged in arrays to circu" lacliLJil Iyly bound a pixel region, e.g., cu",~u, iail ,9 a single pixel, or an array of pixels.
The spacer structure may suitably comprise a support matrix of perpendicularly arranged arrays of elements forming a grid-structure having the spacer elements joined thereto.
Preferably, the spacer elements in the spacer structure comprise columnar elements extending upwardly from the grid support structure.
The unitary spacer structure advantageously is formed, developed, and etched to yield an array of vertically upwardly extending spacer elements extending from and integral with a support grid structure having the spacer elements arranged to bound openings ac-;or"",ocklli"g pu:~it;urlillg in relation to pixel regions forthroughput of electrons from the electron source plate through the spacer structure to the anode plate.
The unitary spacer structure for example may be formed of a developed and etched glass material co,,,,u,i:,i,,g the ,chutufulllled spacer elements.
Co,,t~polldi,,~u,ly, the anode plate may comprise an anode plate substrate metalized with a reflective/conductive metal anode layer of patterned character defining non-metalized openings surrounded by metalized regions of the metalized anode layer, wherein the spacer elements are aligned with the non-metalized openings in the metalized anode layer.
In another aspect, the present invention relates to a method of making a displaypanel cu~,uliai''g an anode plate, an electron source plate including an array of field emitter elements, and a spacer structure including a plurality of spacer elements, i"lt:"uosed between the anode and electron source plates, cor",uriai"ythe steps of:
providing a pllutuae"aili"e material workpiece as a precursor structure of at least a portion of the spacer structure culll,uliainy the spacer elements;
,, , . ... .. = . _ . _ . . , , _ WO 96/03764 2 1 9 6 0 4 0 PCT/US95/lOOU
~ 7 exposing a surface of the phulusenailive material workpiece to phuLusellaili~ lyeffective radiation for sufficient time and at sufficient intensity to phulosenaili~e selected portions of the phutùst:,,ailive material ~.J,hpi~ce, removing non-ph.~ ,osed material from said workpiece to yield at least a portion of the spacer structure including a plurality of spacer elements; and osi"g the spacer structure between the anode and electron source plates, such that the anode and electron source plates are ",d;"ld;"ed in spaced-apart liu~ lahi~J to one another by the spacer structure.
Other aspects, features, and e",bodi",e"ta of the invention will be more fully apparent from the ensuing disclosure and appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a top plan view of a spacer structure according to one e",bo.li",t:"l of the present invention.
Figure 2 is a front elevation view of the Figure 1 spacer structure.
Figure 3 is a bottom plan view of the spacer structure of Fj9UrQ 1.
Flgure 4 is a top plan view of a portion of a field emitter flat panel display assembly, ~,or"~.,iai"a a spacer structure according to one ~",bodi",el,l of thepresent invention, of the type shown in Figure 1, shown superposed on a field emitter color triad array.
Figure 5 is a pe,a~.e~ c view of a flat panel display assembly according to one c:"lbodi"~e"l of the present invention, and featuring spacer structure in au~o,.ld"ce with the invention in an exemplary e:lllbOdi~ lll thereof.
~ Figure 6 is a sectional elevation view of a portion of a flat panel display assembly according to Figure 5, showing the Culll,udllc~llL structure thereof including the emitter and anode plates and spacer structure.
WO 96/0376~ 2 1 9 6 0 4 0 PCT/US95/10028 Figure 7 is a schematic illustration of a process system for photo developing a plluluaellaiIi\le material to form a conical mask region in a substrate.
Figure 8 is a schematic depiction of the conical element formed from the irradiated substrate shown in Figure 7 subsequent to etch removal of phul ~g.osed portions of the substrate.
Figure 9 is a schematic illustration of a process system for irradiating a plluluse~siIi~/e substrate to produce a masked inverted fn,aluco,,iL.c,l region.
Figure 10 is a s- I~c~"~aIic depiction of an inverted fru~tucu"i.al structural element formed by etch removal of irradiated portions of the substrate of Figure 9.
DET~ Fn l:~ESCRIPTION OF THE INVFNTION . AND PREFERRFn ~a~ODlMFNTS THEREOF
The present invention utilizes pllutusellaili~/e materials such as glasses polymers, etc. that can be irradiated, thermally developed and ,he",ica:j etched into complex patterns. The phulus~siIive material may for example comprise a phutusel,sili~/e glass ceramic glass-ceramic material or polymeric material of suitable character. Advantageous glass and ceramic (glass-ceramic) materials suitable for usage include the materials co"""~ y available from Corning Inc.
under the I,~de",~,ks ~ FORM~ and FOTOCERAM~. A particuiarly preferred illustrative material of such type is Fvtulullll~) UV-sensitive glass (Corning Inc.
Corning NY). Such material can provide aspect ratios of up to 4û:1 (aspect ratios as used herein referring to the length or longitudinal dimension of a structure relative to its width or transverse di",el1~iun)~ as well as high quality insulating properties and a."en ~y to forming multilevel structures allowing transverse pathways. Although such materials have inherent potential . ' ~ 'i 1 to use in spacer structures the prior art has not seriously cùllaklelt:d same for flat panel display l~u~ic.lt;on because of their excessive cost and limited size (for example the ~lu,~",~"lioned Fotoform glass is currently available only in 7 x 7 inch maximum sizes.
Accordingly the present invention utilizes such radiation-alterable materials in a novel spacer structure which beneficially utilizes the desirable aspects of .~ 9 materials such as the d~u,~",e"Lioned phulu~u,,,,~ble glass materials, while overcoming their limitations of size and cost.
Accordingly, in a preferred aspect, the present invention cûlltulll,uldl~s the use of relatively small, discreet spacer members, such as is shown in Figure 1.
Figure 1 is a top plan view of a spacer structure 10 in which such spacer member cu",,ur;aes a regular array of standoffs 12, which are vertically upwardly extending elements having upper bearing services 20 for abutting supportive contact with a plate member of a display panel, or such contact with a cc."t::"uondi.,9 opposedly facing spacer structure (i.e., wherein respective facing spacer structures are mated in abutted contact with one another, with for example, one spacer structure being r--- ~ ~ ' with the emitter (cathode) plate of the display panel, and the other spacer structure being ~ ' 3C' with the anode plate of the display article).
The standoffs 12 in this e,,lLu-li,,lt:lll are of truncated pyramidal shape. It will be It:uoylli~t:d that the standoff elements of the support structure may be of any suitable shape or geometry, as necessary or desirable in a given end use ~FF'- - 1.
The standoff elements 20 are i" -uu, " ,eulud in a matrix structure by means of the horizontal support members 14 and the vertical support members 16 (such horizontal and vertical directions referring to the O~ utdt;ull of the spacer structure as shown in Figure 1, it being It:coyll;~:d that the shape of these members and their ul;t:llLdl;ùl1s may be widely varied within the broad practice of the present invention; in general, however, perpendicular and rectangular (square) ~e~ldl;ùnsl~;,us between the members are desirable, for ease of alignment and olitlllldliun relative to the pixels defined by the emitter and anode plates, ashe,~i, Idll~l more fully described.
The standoff elements 20 and the support members 14 and 16 may be integrally formed from a singie block or other form of precursor material. Alternatively, the standoff elements 20 may be separately formed and affixed or secured to the grid~ or matrix formed by support members 14 and 16. In any event, the standoff elements and support members cooperatively formed a unitary support structure which is i,,~u.,uusable between plates or other structural portions of a displaypanel to contribute strength and ",eul,a"iudl integrity to the display article, and to WO 9610376~ 2 1 9 6 0 4 0 PCT/US95110028 permit the display to be evacuated to low vacuum levels without undue static load or, in use dynamic load dt:~icie~ s in the structure and operation of the display panel article.
Fig ure 2 is an elevation view of the spacer structure 10 and Fig ure 3 is a bottom plan view of such spacer structure wherein all parts and features of the structure are col,t,auollui"yly numbered with respect to Figure 1.
The number of "cells" or repeating units in a spacer strurture such as is shown in Figure 1 (such cells referring to the portion of the structure surrounding a given open area 1 8 in the structure) will be d~ ll,i,led by the material and construction, its strength and the frequency of pld~ elll~llt (i.e. number of spacer segments per unit area of the display panel). These spacer structure segments can be individually placed at an d~J~JIu,~ddl~ density across display panels of very large size.
In practice, the spacer structure segments of the type shown in Figures 1-3 may be i,lt~,uosed between respective emitter and anode plates of the display article, in continuous fashion with the spacer segments being contiguous to one another across the full areal extent of the display panel. /'~' u~..iicly the spacer segments may be disposed in spaced-apart l~:ldliullslli,u to one another across such areal extent of the display panel interior volume. The specific dlldllgt:lllelll spacing, size of the spacer segment and frequency may be readily dult:""i"ed without undue exu~lilll~llldliuo by those of ordinary skill in the art based on dt~ ll,,iudliùns of static and dynamic loads and deflection levels of the platesutilized in a given display panel with and without support by the spacer structure.
Fig ure 4 is a top plan view of the spacer structure 10 shown in Fig ures 1 -3 (and whose co""~ont:"l elements are cullt::,,uulldi,l~'y numbered with respect to Figures 1-3) poailioned on a matching field emitter color triad array coi"u,i~i"g a multiplicity of red color elements 26, green color elements 28, and blue colorelements 30, each of said color element triplets (red, green blue) constituting a pixel of the overall array.
This Figure 4 e",bodi",c:lll illustrates the manner in which spacer "en:,iolls can be Illd7~ d and aspect ratios of the support structure reduced by the dlldn~ lll of the emitter color sub-fields within the pixel. The need to stand up an individual high aspect ratio spacer element is eliminated by making the spacer structure segment large enough to cover many pixels, thereby making the aspect ratio of the spacer structure segment relatively small. The spacer structure segment is readily handled and requires no greater alignment control than any other discreetly posilivned element utilized in the display article.
The fine resolution and high aspect ratio capability of the preferred phuLu~u~ dl)le glass material allows the creation of an open structure for both electron passage and lateral gas evacuation within the support structure segment. Concerns about matching of coefficients of exlJallaion are also minimized, since any t~ Jdll:.iVn mismatch is accumulated over only the length of the spacer structure segment and not over the entire length of the display article. The clusters of supports in the spacer structure segment provide greater bearing and racking strength than do isolated individually placed spacer elements, and afford the potential for greatly reducing the number of spacer elements requiring pldc~",elll in the interior volume of the display panel, as dut~,,llliut:d on a unit area of display basis.
The provision of the spacer structure segment of the type illustratively described he,~:.,aboic likewise serves to minimize costs. The small size of the spacer structure segment allows hundreds or even thousands of segments to be fabricated from a plate of precursor (raw) material. The design and divergent exposure process he,t:i"drlt:r more fully described allows complex three-di,,,en:.iu,,al stnuctures of the spacer structure segment to be fabricated with a single exposure which: ' lI;lldlt:S mask ~, ""t:"ts and reduces both processing and mask costs.
Further, the repetitive pattern of the spacer structure segment allows many types of damaged segments (standoff elements) such as those with missins corners, to be employed as long as the remaining spacer structure meets minimum load requirements. Thus, the spacer structure segment tolerates mechanical il,,~.e,r~.,t;vn in the standoff elements and enhances the yield character of the ~dbli " n process, particularly in the instance where the standoff elements are subjected to impact, abrasion, and other forces incident to manufacture and handling which may result in localized i~pe~ ,tivlls in the bearing surfaces of the standoff elements.
The spacer structure of the present invention also has benefits in respect of flashover (arcing) control. Flashover control is of special concern in the rdLIil;dlivn and operation of flat panel field emitter displays because the small spacings clldl d~ ri:~lic of the structure encourage its occurrence. As a countervailing coll:,ideldlioll it is desirable to use as high an anode potential as possible in order to improve efficiency and bl iyl ,I"ess beyond the levels achievable at larger spacing di",t~ iulls. The spacer structures of the present invention are amenable to a, ' ~ ~ of coatings to selected surfaces or portions thereof which enhance high voltage operation while reducing the tendency of the spacer structure to flashover.
Maximum anode potential in operation of the flat panel display is principally governed by the tendency of charge to suddenly and violently travel across the spacer surface as the ~iu~ enliuned flashover pheno",elloll. Flashover generally occurs when the surface charge on the spacer is contiguous enough to fomn an initiating conductive pathway rather than as a result of the spacer structure's bulk insulator properties or defects. The maximum potential therefore is generaliy defined by the absence of flashover. Surface llc:dtlllt~ may be employed to minimize surface charge while electron bu",L,d,d",e"l (due to normaloperation) generally reduces the maximum potential by i"- ,~a:ii"g surface charge.
Figure 5 is a perspective view of aflat panel display 100 colll,uliaillg spaced-apart anode plate 102 and cathode plate 104 of a general type in which the spacer structure of the present invention may advantageously be employed.
Figure 6 is a sectional elevation view of a flat panel display according to one embodiment of the invention. The display panel 205 comprises a bottom plate 206 which may be formed of glass or other suitable material, on the top surface which is provided a series of emitters 207 wherein the emitter cc"",e.:tions areoriented perpendicular to the plane of the drawing page. The emitters 207 are provided with gate row cu,,,,e-liùlls 208, and gate lines 210. The emitters are constnucted over a vertically conducting resistor layer on the substrate. The panel 205 comprises a top plate 212 of a suitable material such as glass. The top plate is ",di"L:.,ed in spaced ItlldLio~ J to the bottom plate by means of spacer elements 213 which feature a flashover control coating 214 on their surfaces exposed to vacuum space 215.
The spacers at the sides of the display may be sealed to the r-- ~ ' d plates bymeans of frits 216 which may for example comprise silica as their material of construction. The top plate 212 may be coated on rts lower surface with a black W096/03764 21 9 6 0 4 0 PCTlUS95/lQ028 ~ 13 matrix material, such as a mixture of barium and titanium, and the RGB phosphors217 are disposed on the top plate against the black matrix material 218. The RGB pl lo~ u,a may optionally be coated with a thin aluminum coating, and may be provided with an IT0 underlayer.
The emitters shown in the panel alldny~",~"l of Figure 6 may alternatively be organized in llwl)o~ llle displays, light panels, sequenceable light strips, andother configurations.
Figures 7-10 illustrate the ~dbl; " I of a spacer structure according to a preferred e",i odi",e"l of the invention.
As shown in Figure 7, a divergent light source 40 is arranged in lightLldll:,lllission l~ldlional,i~, to precursor block 42 formed of a phuluse~silivematerial, such asthe ' ~ el~;u~ed Fotoform glass collllllt:ll,ia"y available from Corning, Inc. (Corning, NY). The light source 40 is selected to emit divergent light beams 46 of a selected suitable wavelength and intensity. The upper (illl~Jillg~ L) surface of the precursor block 42 is masked over a selected area48 by means of masked element 44.
Bysuch d~dngell,~,~t~ the divergent radiation 46 is impinged on surface 49 and into the interior of the precursor block glass material 42. The mask 44 is disposed in relation to the divergent radiation 46 so that the surface region 48 is masked and the radiation path co"t:spu"d;"~ly forms an u"exposecl 42 conical portion of the precursor block 42, with the remainder of the block being pl,~ ,pose~l Thus, the divergent light source produces a controlled degree of exposure under the mask which is d~Jendelll on the distance from the mask or the image plane in the case of projection printing. When mask features are narrow in di~enaions, the light from both sides of the mask crosses within th body of the material, and when developed and etched, results in an illlt~lllledidlt:
height feature. The edges of larger mask features do not meet within the body ofthe precursor block material and therefore result in full height features. In spacer structure segments, height control in the illlt~lllledidl~ structures is non-critical.
The phutu~,~posed precursor block 42 then is baked and fiood exposed to a suitable etchant for the material construction of the precursor block. In such manner, the ~hut ~pùsed portion 52 of the block as shown in Figure 8 is W O 96103764 ~ 2 1 9 6 0 4 0 PC~rN S9S/10028 etchingly removed, yielding the conical-shaped element 50 as a shortened structure in relation to the height or thickness dimension of the precursor block.
Figures 9 and 10 show an analogous process, utilizing a wider mask, to produce a truncated inverted conical shape from the precursor block. In Figure 9, the divergent light source 60 is shown as producing divergent light beams 6 6which impinge on the surface 69 which is partially masked by mask element 64 to provide an u,,t,xposed surface portion 68 on the precursor block 62. The pl,u~ l.osllre is conducted to cw~ lion. The precursor block after phut~ Ypo.~llre then is baked at suitable elevated temperature to develop the phhI ~Q~posed portions of the precursor block, following which the block is subjected to flood exposure of suitable etchant. The etching removes portion 7 2of the precursor block as shown in Figure 10 (wherein the dashed outline denotes the original bounding surfaces of the precursor block 62 (See Figure 9)), yielding the inverted frualu.,o"ical shape of the standoff element 70.
In general, a wide variety of phutusel,aili,le materials may be utilized in the production of spacer structures in acco,dal1ce with the present invention. In the typical process flow, the phutuaell,it;~le material exposed to suitable radiation, e.g., visible or collimated UV light, while selected areas of the phulusensilivematerial workpiece are masked. The ph..~ )osed image then is developed, typically under elevated temperature or other development conditions, followed by optional further development steps including flood exposure in which clear areas of the previously irradiated workpiece are exposed to u" ", ' UV or other radiation without a mask, followed by etch or other removal of the non-masked areas of the workpiece. For example, in the case of a phulusensiti\/e glass material, the unmasked areas of the workpiece may be dissolved in a suitable etchant or reagent medium, such as dilute hydrofluoric acid. Finally, the resulting structural article may be subjected to selected post-treatment ope"~lions such as C~ldlll' ' ' n and/or heat treatment.
Co",,ua,iaon of Figures 8 and 10 shows that the size and shape of the support structure elements may be widely varied by the simple expedient of varying mask size with respect to the resultingly produced shaped member. The technique illustratively described with reference to Figures 7-10 may be employed to produce discreet standoff elements which, as previously described, can be structurally coupled to or secured to other structural elements, e.g., the grid-like matrix of the support structure 10 shown in Figures 1-4. Alternatively, the ~ 15 precursor block utilized to form the standoff elements may be selectively irradiated by suitable masking members to produce a unitary, integral support structure, such as the unitary support structure segment shown in Figures 1-4 hereof.
The anode plate of the flat panel display article of the present invention may be formed and constructed in any suitable manner, within the skill of the art. In apreferred aspect, such anode plate may be aluminized with a reflective/
conductive aluminum anode layer on the surface of a plate of suitable material construction, such as glass. This It:ileuii-~i,uu~ductive aluminum anode layer may suitably be patterned so as to minimize the electric field directly across the spacer structure and to provide an anode ccr",e.,liol1 point. The patterning colll~Jliaes aluminized regions on the anode plate substrate member, and non-aluminized openings defined by the circumscribing aluminized regions. The non-aluminized openings pass and trap incident light more effectively than a black matrix, thereby improving sunlight ,~ of the flat panel dispiay (although a black matrix coating such as titanium or carbon may still be used with such patterned aluminized layer). Such patterned aluminizing of the anode substrate member also reduces the potential for culltdlllilldlion of the interior volume of the flat panel display as a result of the spacer structure p~ujt:utio~ crushing particles or films on the anode surface, or otherwise removing particulate or otherwise removing particulate or finely divided metal or other material which can severely adversely affect the operability of the flat panel display article.
The spacer structure of the present invention may be utilized with surface coatings of various suitable types, which may for example provide enhanced structural or ",ecl1d"i.ial integrity to the spacer structure or otherwise improve its operating (electrical) properties. For example, surface coatings on the spacer structure of slightly leaky insulators may be used to control charging and surface charge accumulation. Examples of such surface coatings include aluminum silicate, alumina, and boron. In such respect, ,uhutusellailive glasses such as the FotoformT~ glass may have very effective surface leakage clldldultlli~ ,s per se as suitable for various ~ a.
.
H will be l~co~u"i~t:d that the phuLufulllli,lg process may be widely varied, asregards the precursor block materials of construction, radiation intensity and wavelength ~hdld~l~liaLil~s, coherency .,I,d,d~,L~riaLics of the radiation, use of other than visible light radiation, e.g., ultraviolet or other actinic radiation, variation in mask size, shape and plact:",e"L, variation in development (e.g., baking WO 96/03764 2 1 9 6 0 4 0 PCT~S9~/10028 conditions) subsequent to initial radiation exposure, and variation in etching reagents and etch conditions, etching here being broadly construed to include any sol~ Ih~ ti~ln process by means of which material is removed from a precursor workpiece sl~hseq~ent to radiation exposure and development.
As an alternative to etching removal of material from photodeveloped v.ol h,uieces, it is within the purview of the present invention to utilize non-etching removaltechniques, including Ille.,l,a"icdl removal processes and procedures, either for bulk removal of material, or for finishing of rough-formed support structures.
In respect of electrical clldldulc~ dtiull and o,ut;"~i~dlion of support structures within the broad purview of the present invention, the testing and o,uLi,,,i~dLion may be carried out in a manner within the skill of the art. For example, electrical testing may be carried out by pldcellle:llL of spacer structures between conductive surfaces onto plates, with the imposition of a variable potential difference across the spacer structure. Leakage occurrence then can be measured together with the occurrence and frequency of flashover events. The cathode plate may in such testing comprise a field emitter array, positioned relative to the spacer structure so that pixels in known positions may be selectively activated, for purposes of measurement while the activated pixels are conducting. By use of different pitches for pixel and spacer co""~on~"L~, pixels with different ,UlUAillliti~s to the spacer structure can be activated without breaking vacuum conditions, or otherwise changing empirical conditions, to thereby test the spacer structure's sensitivity to pixel alignment.
While the invention has been illustratively described with respect to specific preferred features, aspects, and elllL)odi,lld,lt~, it will be ,t:coy"i~ed that the invention may be widely varied, and that numerous other variations"" ' ' ls and alternative elllLJodi",~llt:, are possible, within the spirit and scope of the present invention.
INDUSTRIAL APPLICABILITY
The flat panel displays of the invention have utility in a wide spectrum of f p,B- ~- )5, including defense, scientific, medical, educational, business and rdul~ ~- nal usages, in device ~ ns such as portable work stations, lap tops, palm tops, pen-based pads, video phones, cellular phones, digital high definition television (HDTV), and the like.
.....
Claims (19)
What Is Claimed is:
1. A display panel comprising:
an anode plate;
an electron source plate comprising an array of field emitter elements; and spacing means for maintaining said anode plate and electron source plate in spaced relationship to one another said spacing means comprising a planar matrix support structure of intersecting elongate members which define a plurality of individual cells therebetween, said matrix support structure being formed as a unitary spacer structure having photoformed spacer elements integrally joined perpendicularly to the planar support structure at points of intersection of theintersecting elongate members and interposed in bearing and supporting relationship between said anode and electron source plates said individual cellsdefining pixel regions of the display panel.
an anode plate;
an electron source plate comprising an array of field emitter elements; and spacing means for maintaining said anode plate and electron source plate in spaced relationship to one another said spacing means comprising a planar matrix support structure of intersecting elongate members which define a plurality of individual cells therebetween, said matrix support structure being formed as a unitary spacer structure having photoformed spacer elements integrally joined perpendicularly to the planar support structure at points of intersection of theintersecting elongate members and interposed in bearing and supporting relationship between said anode and electron source plates said individual cellsdefining pixel regions of the display panel.
2. A display panel according to claim 1, wherein said photoformed spacer elements are arranged at each of said points of intersection of the intersectingelongate members to circumscribingly bound each of the individual cells.
3. A display panel according to claim 1 wherein each of the pixel regions comprises a single pixel.
4. A display panel according to claim 2 wherein each of the pixel regions comprises an array of pixels.
5. A display panel according to claim 1 wherein the intersecting elongate members are perpendicularly arranged forming a grid-structure having the spacer elements joined at the intersections thereof.
6. A display panel according to claim 5 wherein the spacer elements in said spacer structure comprise columnar elements extending upwardly from the grid-structure.
7. A display panel according to claim 1, wherein the intersecting elongate members and photoformed spacer elements of said spacing means are formed, developed, and etched from a unitary block of photoformable material to yield a support grid structure having said spacer elements which bound openings which define the pixel regions for throughput of electrons from the electron source plate through the spacing means to the anode plate.
8. A display panel according to claim 1, wherein the unitary spacer structure isformed of a developed and etched glass material comprising said photoformed spacer elements.
9. A display panel according to claim 1, wherein the anode plate comprises an anode plate substrate metalized with a reflective/conductive metal anode layer of patterned character defining non-metalized openings surrounded by metalized regions of the metalized anode layer, wherein the spacer elements are aligned with the non-metalized openings in the metalized anode layer.
10. A method of making a display panel comprising an anode plate, an electron source plate including an array of field emitter elements, and a spacer structure including a plurality of spacer elements, interposed between said anode and electron source plates, comprising the steps of:
providing a photosensitive material workpiece as a precursor structure of at least a portion of said spacer structure comprising said spacer elements;
exposing a surface of said photosensitive material workpiece to photosensitizingly effective radiation for sufficient time and at sufficient intensity to photosensitize selected portions of the photosensitive material workpiece;
removing non-photoexposed material from said workpiece to yield at least a portion of said spacer structure including a plurality of spacer elements, and forming the spacer structure to comprise a planar matrix support structure of intersecting elongate members, which define a plurality of individual cells therebetween, as a unitary spacer structure having photoformed spacer elements integrally joined perpendicularly to the planar support structure at points of intersection of the intersecting elongate members; and interposing the spacer structure between said anode and electron source plates, such that the anode and electron source plates are maintained in spaced-apart relationship to one another by said spacer structures and so that the individualcells define pixel regions of the display panel.
providing a photosensitive material workpiece as a precursor structure of at least a portion of said spacer structure comprising said spacer elements;
exposing a surface of said photosensitive material workpiece to photosensitizingly effective radiation for sufficient time and at sufficient intensity to photosensitize selected portions of the photosensitive material workpiece;
removing non-photoexposed material from said workpiece to yield at least a portion of said spacer structure including a plurality of spacer elements, and forming the spacer structure to comprise a planar matrix support structure of intersecting elongate members, which define a plurality of individual cells therebetween, as a unitary spacer structure having photoformed spacer elements integrally joined perpendicularly to the planar support structure at points of intersection of the intersecting elongate members; and interposing the spacer structure between said anode and electron source plates, such that the anode and electron source plates are maintained in spaced-apart relationship to one another by said spacer structures and so that the individualcells define pixel regions of the display panel.
11. A method according to claim 10, wherein the array of field emitter elements and said anode plate define a multiplicity of pixels, and wherein the photoformed spacer elements circumscribingly bound a predetermined pixel region.
12. A method according to claim 11, wherein the pixel region comprises a pixel array.
13. A method according to claim 11, wherein the pixel region comprises a single pixel.
14. A method according to claim 10, wherein the spacer structure comprises a support matrix of perpendicularly arranged arrays of elements forming a grid structure having the spacer elements joined thereto.
15. A method according to claim 14, wherein the spacer elements in said spacer structure comprise columnar elements extending upwardly from the grid structure.
16. A method according to claim 10, wherein the spacer structure is formed, developed, and etched from a unitary block of photoformable material to yield a support grid structure having said spacer elements which bound openings which define the pixel regions for throughput of electrons from the electron source plate through the spacing means to the anode plate.
17. A method according to claim 10, wherein the spacer structure is formed of a developed and etched glass material comprising said photoformed spacer elements.
18. A method according to claim 10, wherein the anode plate comprises an anode plate substrate metalized with a reflective/conductive metal anode layer of patterned character defining non-metalized openings surrounded by metalized regions of the metalized anode layer, and wherein the spacer elements are aligned with the non-metalized openings in the metalized anode layer.
19. A display panel comprising:
an anode plate;
an electron source plate comprising an array of field emitter elements; and spacing means for maintaining said anode plate and electron source plate in spaced relationship to one another, said spacing means comprising a planar matrix support structure of intersecting elongate members, which define a plurality of individual cells therebetween, said matrix support structure being formed as a unitary spacer structure having spacer elements integrally mounted to and extending perpendicularly from the planar support structure at points of intersection of the intersecting elongate members and interposed in bearing andsupporting relationship between said anode and electron source plates, said individual cells defining pixel regions of the display screen, and wherein said spacer elements have been formed of photoreactive material which has been selectively shaped by preferential etching of the material and coated with an insulative layer for charge leakage control.
an anode plate;
an electron source plate comprising an array of field emitter elements; and spacing means for maintaining said anode plate and electron source plate in spaced relationship to one another, said spacing means comprising a planar matrix support structure of intersecting elongate members, which define a plurality of individual cells therebetween, said matrix support structure being formed as a unitary spacer structure having spacer elements integrally mounted to and extending perpendicularly from the planar support structure at points of intersection of the intersecting elongate members and interposed in bearing andsupporting relationship between said anode and electron source plates, said individual cells defining pixel regions of the display screen, and wherein said spacer elements have been formed of photoreactive material which has been selectively shaped by preferential etching of the material and coated with an insulative layer for charge leakage control.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US28035594A | 1994-07-25 | 1994-07-25 | |
| US280,355 | 1994-07-25 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2196040A1 true CA2196040A1 (en) | 1996-02-08 |
Family
ID=23072726
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2196040 Abandoned CA2196040A1 (en) | 1994-07-25 | 1995-07-25 | Flat display spacer structure and manufacturing method |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP0772884A4 (en) |
| CA (1) | CA2196040A1 (en) |
| WO (1) | WO1996003764A1 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5629583A (en) * | 1994-07-25 | 1997-05-13 | Fed Corporation | Flat panel display assembly comprising photoformed spacer structure, and method of making the same |
| US5898266A (en) * | 1996-07-18 | 1999-04-27 | Candescent Technologies Corporation | Method for displaying frame of pixel information on flat panel display |
| WO1998040901A1 (en) * | 1997-03-10 | 1998-09-17 | Micron Technology, Inc. | Method for forming spacers in flat panel displays using photo-etching |
| FR2764109A1 (en) * | 1997-05-30 | 1998-12-04 | Commissariat Energie Atomique | SPACERS FOR FLAT VISUALIZATION SCREEN |
| FR2764729A1 (en) * | 1997-06-13 | 1998-12-18 | Commissariat Energie Atomique | METHOD OF MANUFACTURING SPACERS FOR FLAT VISUALIZATION SCREEN |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4935235A (en) * | 1979-05-24 | 1990-06-19 | The Regents Of The University Of California | Non-passageable viruses |
| US5017558A (en) * | 1980-01-14 | 1991-05-21 | The Regents Of The University Of California | Synthetic vaccine peptide epitomes of hepatitis B surface antigen |
| JPS60161999A (en) * | 1984-02-02 | 1985-08-23 | Chemo Sero Therapeut Res Inst | Peptide |
| US4818527A (en) * | 1986-12-09 | 1989-04-04 | Scripps Clinic And Research Foundation | T cell epitopes of the hepatitis B virus nucleocapsid protein |
| US4923421A (en) * | 1988-07-06 | 1990-05-08 | Innovative Display Development Partners | Method for providing polyimide spacers in a field emission panel display |
| NL9100122A (en) * | 1991-01-25 | 1992-08-17 | Philips Nv | DISPLAY DEVICE. |
-
1995
- 1995-07-25 CA CA 2196040 patent/CA2196040A1/en not_active Abandoned
- 1995-07-25 EP EP95930801A patent/EP0772884A4/en not_active Withdrawn
- 1995-07-25 WO PCT/US1995/010028 patent/WO1996003764A1/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| EP0772884A4 (en) | 1997-12-10 |
| EP0772884A1 (en) | 1997-05-14 |
| WO1996003764A1 (en) | 1996-02-08 |
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