CA1166504A - Fabrication of arrays containing interlaid patterns of microcells - Google Patents

Abstract

Abstract of the Disclosure In the forming of microcellular arrays, such as those useful in photography, a closure is positioned to overlie a plurality of microcells forming a planar array.
The closure is selectively removed from one set of micro-cells forming an interlaid pattern with a second set of microcell so that the contents of the first set of micro-cells can be changed without concurrently changing the contents of the second set of microcells.

Description

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AN IMPROVEMENT IM THE FABRICATION OF ARRAYS
CONTAINING INTERLAID PATTERNS OF MICROCELLS
Field_of the Invention The present invention is directed to A proceBs of separately addressing at least one of two or more inter-laid sets of microcells forming an array. The invention is also directed to microcellular elements, including both elements useful in practicing this process and elements which are the products of this process. In a specific aspect this invention relates to photographic elements and processes for their manufacture.
Back~round of the Invention This invention is an improvement on K. E.
Whitmore Canadian Serial No. 343,727, filed January 15, 1980, commonly assigned, titled IMAGING WITH NONPLANAR
SUPPORT ELEMENTS. Whitmore applies to photographic imaging the use of supports contalning arrays of microcells (or microvessels) opening toward one ma~or surface. In a variety of different forms the photographic elements and components disclosed by Whitmore contain an array of microcells in which first, second, and, usually, th~rd sets of microcells are interspersed to form an interlaid pattern. In a typical form three separate sets of microcells, each containing different subtractive pri-~5 mary (i~e., yellow, magenta, or cyan) or ~dditive primary(i.e., blue, green~ or red) imaging component, ~re inter-Iaid. Preferably each microcell of each set is positioned laterally next ad~acent at least one microcell of each of the two remaining sets. The microcells are intentionally sized 80 that they are not readily individually resolved by the human eye, and the interlaid relationship of the microcell ~ets further aids the eye in fusing the imaging components of the separate sets of microcells into a multicolor image.
In one specifically preferred embodiment dis-closed by Whitmore, cyan, magenta, and yellow dyes or dye precursors of alterable mobility are associated with L~ 5~4 immobile red, green, and blue dyes or pigments, respec-tively, each present in one of the first, second, and third 8ets of microcells, and the microcells are over-coated with a panchromatically sensitized silver halide emulsion layer. By exposing the silver halide emulsion layer through the microcells and then developing, an addi-tive primary multicolor negative image can be formed by the microcellular array and the silver halide emulsion layer while cyan, magenta, and yellow dyes can be trans-ferred to a receiver in an inverse relationship to image-wise exposure to form a subtractive primary positive multicolor image. The foregoing is merely exemplary, many other embodiments being disclosed by Whitmore.
A technique disclosed by ~hitmore for differen_ tially filling microcells to form an interlaid pattern calls for first filling the microcells of an array with a sublimable material. The individual microcells forming a first set within the array can then be individually addressed with a laser to sublime the material initially occupying the first set of microcells. The emptied micro-cells can then be filled by any convenient conventional technique with a firs~ imaging component. The process is repeated acting on a second, interlaid set of microcells and filling the second set of emptied microcells with a second imaging component. The process can be repeated again where a third set of interlaid microcells is to be filled, although individual addressing of microcells is not in tbis instance required. This approach is suggested ~ by Whitmore to be useful~in individually placing triads of additive and/or subtractive primary materials in first, second, and th;rd sets of microcells, respectively.
Summary of the Invention WhiIe the process described by Whitmore for differentially filling microcells in an interlaid pattern 35 i6 u~eful, the present invention represents an improvement in several respects. Specifically, the present invention is more efficient in its use of materials. It creates less waste of valuable materials and obviates any neces-, ... .. .
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s~-3-sity of employing sublimable materials. The present pro-cess requires less energy to obtain empty ~ets of micro-cells. For example, less laser energy is required. Any risk of only partially e~ptying microcells is reduced.
Finally, the present invention offers the capability of initially filling the microcells with one or more nonsub-limable materials which are intended to remain permanently in some of the microcells. Other advantages of this invention will become apparent from the detailed descrip-tion of preferred embodiments.
In one aspect, this invention i9 directed to animprovement in a process comprising forming in a support having first and second major surfaces a planar array of microcells opening toward the first major surface and selectively altering the contents of a first set of the microcells in relation to a second, in~erlaid set of the microcells. The process is characterized by the improve-ment comprising, selectively altering the contents of the microcells by positioning adjacent the first major sur-face, means for closing both the first and second sets ofmicrocells and selectively removing the closing means from ; the first set of microcells to permit selectively altering the contents of the first set of microcells without con-currently altering the contents of the second set of microcells.
In another aspect this invention is directed to the combination comprising support means having first and second major surfaces and forming a planar array of micro-cells opening toward the first major surface and a destructible membrane overlying the first major surface, thereby closing a plurality of the microcells of the planar ar~ay.
The invention can be more fully appreciated by the fo~lowlng descr~pt;~n of preferred embodiments con-sidered in conjunction with the drawings, in which Figure lA is a plan view of a support;
Figure lB is a section taken along section linelB in Figure lA;

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Figures 2 and 3 are sectional details of alter-. nate supports;
Figure 4A is a plan view of a multlcolor filter element;
Figure 4B is a section taken along section line 4B in Figure 4A;
Figures SA through 5D are sectional views showing progressive stages of construction of the multicolor filter element; and Figure 6 is a sectional view of a multicolor image transfer photographic element constructed according to th~s invention.
The drawings are of a schematic nature for con-venience of viewing. Since the individual microcells are lS too small to be viewed wlth the unaided human eye, the microcells and elements in which they are contained are greatly enlarged. The depth of the microcells have also been exaggerated in relation to the ~hickness of the supports, which typically is from 50 to 500 or more, times greater.
Description of Preferred Embodiments A support is employed in the practice of this in~ention having~formed therein an array of microcells.
The support and its microcells can be similar to those described by Whitmore, cited above.
A~specific preferred support 102 is schematically illustrated in~Figures lA and lB. ~The~support has sub-tant-ally~parallel first and second ma~or ~urfaces 104 and 106. The~supp~ort defines a plurality of microcells (or microves~sels)~108, which open toward the first ma~or surfacs of the support. The microcells are defined in the support by an interconnecting netwbrk o lateral walls 110 which are integrally ~oined to an underlying portion 112 so that the support ACtS as a barrier between ad~acent microcells. The underlying portion o the support defines the bottom wall 114 o~ each microcell.

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The dashed line 120 defines a boundary of an ~rea unit containing a single microcell, The remaining depict-ed area of the support is formed by area units essent~ally identical to that within the boundary 120.
Alternative supports employed in the present invention can ~e varied in their ~eometrical configura-tions and structural makeup. For example, Figure 2 sche-matically illustrates in section a unit area of a support 202 provided with a first major surface 204 and a second, substantially parallel major surface 206. A microcell 208 opens toward the first major surface. The support is comprised of a plurality of repeated similar unit areas.
The microcells are formed so that the support provides inwardly sloping walls which perform the functions of both the lateral and bottom walls of the microcells 108. Such inwardly curving wall structures are more conveniently formed by certain techniques of manufacture, such as etch-ing, and also can be ~etter suited for redirecting expos-ing radiation toward the interior of the microcells in photographic applications.
In Figure 3 a unit area of a ~upport 300 is ; shown. The support is comprised of a first support ele-ment 302 having a first major surface 304 and a second substantially parallel major surface 306. Joined to the first support element is a second support element 308 which is provided~in each repeated unit area with an aper-ture 310. The second support element is provided with an outer major surface 312. The walls of the second support element forming the ~aperture 310 and the first major sur- -face of the fir~t~support element together define a micro-cell. The support is ~comprised of repetitions of the unit area shown.
The microcells are located in the supports in a predetermined, controlled relationship to each other. The microcel 18 are relati~ely spaced in a predetermined, ordered manner to form an array. It i5 usually desira~le and most efficient to form the microcells 80 that they are aligned along at least one axis in the plane of the sup-, -~

port surface. For exsmple, microcells in the configura-tion of hexagons (preferred for.arrays containing three interlaid sets of microcells differing in the material contained therein~, are conveniently aligned along three support surface axes which intersect at 60 angles. It is generally preferred that the microcells be positioned to form a regular.pattern. It is recognized that adjacent microcells can be v~ried in spacing to permit alterations in visual effects and for.other.purposes. Although Figure lA shows regular hexagonal microcells, any polygonal, circular, elliptical, or.other.predetermined recurring microcell configuration can be employed, as may be con-venient.
As disclosed by Whitmore, the foregoing supports are merely illustrative of a variety of possible configu-rations. In one variant form the microcells can be of extended dept~. In another.variant form a relatively deformable support element can be coated on a relatively nondeformable second support element and embossed. In section such a support differs from support 300 in that a thinned portion of the second support element 308 extends beneath the microcells rather.than the second support ele-ment being apertured, as shown. Hexagonal microcells are preferred for.multicolor.photographic applications, as described more fully below.
It is also possible to coat any and all of the supports described above to alter.their.surface proper_ ties. For.example, one or.a combination of thin subbing layers can be coated on one major.surface of the supports and extended into the microcells, thereby coating their.
walls without filling the microcells. Such layers can be used to promote adhesion of materials to be introduced into the microcells, to increase or.decrease reflection of radiation, or.to perform other.modifying functions.
Although one major ~urface of the supports i9 ~hown in e~ch instance to be pla~ar, it can take other.
configurations. For.example, sepal~te ~r~ys o micro-cells can open toward each major.surface of the supports.

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Depending upon the application, the microcells of those separate arrays can be intentionally aligned, mi6aligned, or.not intentionally oriented with respect to each other.
The major.surface shown to be planar.can alternatively be lenticular. In a preferred exemplary form a single lenti-cule can be coextensive with the boundary of the area 120.
For photographic applications it i6 frequently desirable to form elements containing two or three sepa-rate interlaid sets of microcells, Three interlaid sets of microcells can, for.example, contain interlaid segments of blue, green, and red filters, the blue, green, and red dyes or.pi~ments forming the filter~ each being confined to a separate set of microcells. Alternatively, the separate sets of microcells can contain radiation-sensi-tive imaging materials, each sensitive to a differentportion of the visible spectrum--e.g., blue, green, and red responsive silver.halide emulsions, each confined to a separate set of microcells. In still another.form, the three sets of microcells can contain suktractive primary imaging dyes or dye precursors--i.e., cyan, magenta, and yellow imaging dyes or.dye precursors, each confined to a separate set of microcells. The microcells can also contain combinations of filter~ radiation-sensitive, and imaging materials.
: 25 To illustrate a specific application for.the microcellular.supports, in Figures 4A and 4B a multicolor.
filter.element 400 is illustrated~ As shown, the filter.
element is comprised of a support 102 forming a plurality of identical hexagonal microcells 108. The lateral walls : 30 110 separating adjacent microcells are dyed to reduce light transmission therethrough while the underlying portions 112 of the support, which form the bottom walls of the microcells, are substantially transparent. As :: sbown, the multicolor filter.element is comprised of red, green, ~nd blue filte~ each divided in~o discrete seg-ments R, G, and B. The filter.se~ments are located in fir~t, second, and third sets o microcells in an inter_ laid pattern.

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The multicolor filter element 400 can be employed for additive multicolor imaging, ~uch as illustrated by Dufay U.K. Patent 15,027 (1912~, Dufay U.S. Pa~ent 1,003,720, and James, The Theory of the Photo~raphic Process, 4th Ed., Macmillan, 1977, p. 335. By exposing through the multicolor filter.a panchromatically respon-sive imaging material--such as a panchromatically sensi-tized silver halide emulsion, it is possible to form a multicolor image. For instance, a negative-working silver halide emulsion can produce a multicolor negative image following exposure and development when viewed through the multicolor filter. A direct-positive imaging material will similarly produce a positive multicolor image.
The interlaid pattern of microcells illustra~ed is particularly advantageous from a visual standpoint, since each filter.segment is surrounded by an equal number.
of segments of each of the two remaining filters. In tbis way the eye can readily blend the laterally separated filter segments in viewing an image. Also, printing : 20 through a multicolor.negative image formed by the filters and radiation-sensitive imaging material to form a multi-color positive is facilitated by the spatial relationship of the separate sets of microcells.
It is, of course, recognized tha~ other.interlaid patterns of filter segments are possible. For example, instead of being interlaid in tbe manner.shown, the blue, ; green, and red filter segments can form separate rows of microcells. For instance, a row of filter.segments of one color can be interposed between two filter.6egment rows, one of each of the two remaining additive primary colors.
: Different interlaid patterns can also occur.as a result of devoting unequal number:s of microcells to the different filters. For example, it i8 recognized that the human eye obtains ~st o~ it~ infor~htion from the green portion of the spectTum. Less information îs obtained from the red portion of the spectrum, and the least amount of lnforma_ tion is obtained from the blue portion of tbe spectrum.
Bayer.U.S. Patent 3,971,065 discloses an interlaid addi-.; .

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5~`~_9_ tive pri~ary multicolor filter segment pattern in which the gree~ segments occupy half of the total array area, with red and blue filteF segments each occupying one half of the remaining area of the filter array. Such filters can be formed by the present invention, if desired.
Dufay and others recognized the desirability of providing segmented interlaid filters in the smallest attainable sizes. Lateral spreading of the materials forming the separate filter segments has, however, posed a limitation on obtaining small filter segments. For example, w~en dyes from adjacent segments mix, even in edge regions, unwanted shifts in hue can occur. Whitmore, cited above, recognized that lateral spreading can be overcome by placing the filter materials in microcells.
The lateral walls 110 of the support 102 for~ a physical barrier to lateral spreading and mixing of filter materi-als.
Notwithstanding Whitmore's contribution to the art, the present invention provides an improved approach for selectively introducing materials into interlaid sets of microcells. It is to be recognized that the supports as shown in the drawings are greatly enlarged and contain some deliberate distortions of relative proportions. Most notably, the microcells have been greatly enlarged for purposes of illustration. In actuslity the microcells are intentionally formed of a size that cannot be readily resolved by the unaided human eye, and in general the microcells can only be individually viewed microscopi-cally. Thus, the vast majority of approaches for placing materials in interlaid set of larger cells are foreclosed ~; to the placement of materials seIectively in interlaid sets of microcells.
The method of the present invention is generally applicable to tbe for~ation of elements containing in a fir~t set o~ microcells a first material or combination of materials and in at least one other~ interlaid set of microcells a different material or combina~ion of materi-; als. Figures 5A through 5D illustrate the application of ,,.

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the method of this invention to the manufacture of an element containing three interlaid sets of microcell~ each containing a different material or combination of materi-als.
In Figure 5A the ~upport 102 is shown in the form described above for use in the multicolor filter element 400. Adjacent the first major surface 104 of the support is a membrane 502. The mem~rane overlies and closes the microcells 108 of the support. The membrane is comprised of or entirely formed of a film-forming organic polymer and is thin as compared to the lateral walls 110 of the support. The membrane is preferably of a thickness of from about 5 to 50 percent that of the lateral walls. The microcells preferably initially contain a readily remov-able thermal insulator, such as air, although any readilyremovable material could be initially present.
While any convenient conventional technique can be employed for forming the membrane and locating it in the position shown in Figure 5A, in most instances the membrane will be about 0.2 to 1 micron in thickness so that many approaches useful in forming thicker membranes will not be useful in forming or positioning the membrane 502. In one specific preferred approach the membrane is formed by casting a film-forming polymer in a volatile solvent on the surface of a liquid in which the polymer does not readily dissolve, such as water~ contained in a reservoir. The film is allowed to at least partially set by solvent evaporation. To protect the film from distur_ bances a floating frame can be laid on the film, if desired. By slowly raising the support 102 from within the reservoir to the surface of tbe water, the membrane can be positioned on the first major 0urface of the support in the desired position without endangering the integrity of the membrane. Any ~ater initially trapped in the microcell~ will evaporate if the element is allowed to stand for a period of tim0. The minimal thickness of the membrane allows both air and water vapor to diffuse there-- through, so that in a period of time an element is pro-~, ' .

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duced as æ~own in Figure 5A having only air in the micro-cells. lt is appreciated th~t other volatile or highly thermally nonconductive liquids can be substituted for water in providing a casting surface, if desired. Instead of raising the support through the water, the support can be simply laid on the dry upper surface of the membrane with the first major surface of the support contacting the membrane.
The next step of the process is to selectively open the microcells intended to form one of the interlaid sets. Any technique which allows one set of microcells to be opened selectively can be employed. It is preferred to employ radiation striking the membrane to open the set of microcells. Any of the various techniques disclosed by Whitmore, such as the use of masks, can be employed.
According to a preferred technique a laser beam is sequen-tially aimed at the microcells forming one interlaid set.
This is typically done by known laser scanning techniques, such as illustrated by Marcy U.S. Patent 3,732,796, Dillon ~0 et al U.S. Patent 3,864,697 and Starkweather et al U.S.
published patent application B309,860.
Followîng a specific, preferred technique two lasers are employed. One of the lasers is of sufficient intensity to provide the desired alteration of the 25 ~membrane overlying the microcells. The second laser is used only to position accurately the first laser and can differ in wavelength snd can be of lesser intensity. The first and second laser beams are laterally displaced in the plane of the membranes by an accuratèly determined - 30 distance. By empl~oying a photodetector to receive light transmitted through or re1ected from the upport from the second laser, it can be~determined when a microcell or a lateral wall i6 aligned ~ith the second laser beam. In the illust~ated preferred form, in which the support bottom walls are subs~antially transparent and the lateral walls are dyed, a subs~antial change in light intensity sensed by the photodetector will occur as a function of the relative position of the support and laser beam. In :~:

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2-other.instances differences in reflection or.refraction between the botto~ ~nd la~eral walls for~ing the micro-cells can be relied upon to provide information to the photodetector. Once the position of the ~econd laser.with respect to a microcell is ascertained, the position of the first laser.with respect to a microcell can also be ascer_ tained, since the spacing between the lasers and the center-to-center spacings of the microcells are known.
Depending upon the pattern and accuracy of exposure desired, indexing with the second laser.can be undertaken before exposing each microcell with the first laser, only once at the beginning of exposure of one microcell ~et, or at selected intermediate intervals, such as before each row of microcells of one set is exposed.
When a first laser.scan is completed, the support is left with one open microcell set while the remaining intetlaid microcell sets are substantially undisturbed.
Instead of sequentially laser.exposing the microcells in the manner indicated, exposure through a mask can be undertaken, as is well known. Laser.scanning exposure offers the advantages of eliminating any need for.mask preparation and alignment with respect to the microcells prior.to opening one microcell set.
When radiant energy from a laser or.other source ~: 25 impinges on the membrane in one or.more areas correspon-ding to one microcell or.microcell set, the membrane is locally heated. It is specifically preferred to impinge radiant energy selectively over.that portion of the membrane lying at or.near.the cen~er.of ~he underlying : 30 m~icrocell, Since tbe membrane is extremely thin, its heat : capacity i8 low. That i6, very little heat energy is required to raise it~ temperature. ThuS, a laser.beam, for.example, can quickly raise the temper~ture of the organic me~rane to it~ decomposition point in a selected area overlying a microcell. Since the membrane is no more than half the thickness of the late~al walls and usually of much less thickness, the lateral walls do not rise in temperature to the came extent as the membranel even when .

~ 5 both t~e membrane and support sre formed of the ~ame materiat. Being thicker~ the lateral walls have a higher heat capacity, slowing their increa~e in temperature.
Second, if the radiant energy is confined to the area near the center of tbe underlying microcell, heat must be con-ducted laterally by the membrane to the lateral walls; but being very thin, the membrane is an inefficient thermal conductor. Selective thermal destruction of the membrane can be enhanced by forming the support of a more thermally stable material, ~o that if the membrane and support should approach the same temperature, the membrane will still be selectively destroyed.
It is specifically contemplated to employ a radiant energy source and membrane in combination which allows the membrane to absorb efficiently the radiant energy. The film-forming polymer.composition can be modified by incorporating an ultraviolet absorber, dye, or.
infrared absorber. Independently~ an absorption promoting material can be coated over.the membrane once it is formed in place. For example, the membrane can receive a deposit of lamp black by being passed over.an open flame to increase its absorption of radiant energy. In addition to increasing the radiant energy absorption by the membrane, the support can be chosen so that it is relatively non-absorbing in the spectral regioo of the radiant energy.
: From the foregoing it is apparent that, by selec-tively addressing areas of the membrane overlying one set : of microcells, it is possible to open selectively one set of microcells without affecting adjacent sets of micro-cells and without damaging the support. Thereafter~ the opened set of microcells can be filled by any convenient conventional tecbnique without filling the remaining :~ microceIls. This i~ illustrated by reference to Figure SB, in ~hc~ the membrane 502 has been modified by the introduction of apertures 504 corresponding to one under_ lying set of microcell~. For.purpo~es of illustration, the open set of microcells is shown to be filled with material forming the blue filter.segments B.

1~6~iS(~4 In filling the open set of microcells, a tech-nique is prefer~bly chosen which places minimal phy6ical stress on the mem~rane~ Fo~ ex~mple, in the form illus-trated, an aqueous solution of blue dye or suspension of blue pigmen~ can be introduced into the open set of micro-cells while placing only minimal stress on the remaining membrane. Upon evaporation of water, the blue dye or pigment is left in the open set of microcells. Filling can be repeated, if desired, until the desired optical density of blue dye or pigment is obtained in the open microcells. This approach can be practiced with any material or combination of materials desired to be placed in the microcells and any compatible volatile liquid. By proper choiceæ of materials and liquids layering can be achieved within the microcells, if desired. In an alter-native form the filling material can take the form of a fine particulate which is gently brushed into the micro-cells. The particles, of course, have mean diameters substantially less than the width of the microcells. The particles can, if desired, be fused in place. For exam-ple, many particulate materials will fuse simply by stand-ing under conditions of high humidity. Fusion by mild heating is also contemplated.
In Figure 5C a second, interlaid ~et of micro-25 cells is shown opened and filled to form green filtersegments G. The techniques described above for openin~
and filling the first set of microcells can be repeated unchanged, except for the substitution of green filter material. When this stage of the process is reached, only - 30 discrete segments 506 of the original membrane remain overlying the third, interlaid ~et of microcells.
To permit the third, interlaid set of microcells to be filled, the techniques described above for opening the first and secand ~et~ of microcells can be repeated, except that a red filter material is substituted. The product, as shown in Figure SD, i8 the multcotor filter element 400.

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It will be apparent that the last set of micro-cells can be filled by a ~roader.selection of techniques than the first and any intermediate sets o~ microcell8.
In opening the last set of microcells the techniques employed for removing the membrane need not be areally selective. For example, in the specific embodiment illus-trated, since the membrane can be entirely destroyed in opening the last set of microcells, it is not necessary to address the membrane segments 506 selectively with radiant energy, ~ather, the element as shown in Figure 5C can be uniformly exposed to radiant energy to destroy the mem-brane segments 506. Alternatively, the membrane segments remaining can be removed by laminating it to a support to which it adheres in preference to the first major.sur~ace 104 and then simply lifting the membrane segments from the first major.surface. Adhesion of the membrane 6egments to another.support can be accomplished by any one of a ~ide variety of conventional laminant transfer techniques.
It is not even necessary to remove the membrane segments 506 before filling. By employing filling tech-niques which are in themselves capable of destroying the membrane segments, the steps of opening and filling the last set of microcells can be combined. ~or example, by doctor blade coating the element as shown in Figure ~C
with a re~ filter material, the membrane segments can be collapsed into t~e underlying microcells while leaving room for.the red filter.material to also enter:the third set of microcells.
~ The foregoing microcell filling technique is particularly well suited to applications in which the microcells of each set, except the last, are intended to be substa~tial~y entirely filled. Thus, any material intended to be placed in a subsequent set of microcells after the first set ~as ~een opened and filled cannot enter.tbe ~irst set o~ micTocells, since material filling these microcells prevents additional material from enter_ ing. Any slight amount of material that may deposit above the ~irst, filled set of microcells in filling the second .
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or subsequent sets can in many application~ be ignored, Alternativeiy, the additional surface material can be removed ~y gentLy a~rading the first major surface 104 of the support after all of the microcells have been filled.
For example, the major surface 104 of the support can be swabbed or skived with a doctor.blade to remove any mater-ials over and above those which are contained in the microcells.
In a variant approach, which is particularly applicable to only partially filling the microcells or maintaining a high degree of separation of materials being placed in separate sets of microcells, after the first set of microcells are opened and partially filled to the extent desired, a second membrane is positioned over the first major.surface of the support. If desired, the first membrane can be entirely removed before positioning the second membrane, as by using the laminant or destruction techniques described above. Where ~he membranes are com-paratively thin, so that the multiple layers of membrane : ~0 can still be thermally destroyed selectively without damaging the support lateral walls, the second membrane can be positioned over the first, now apertured, mem-brane. The first and second membranes are then selec-tively destroyed in areas overlying the second ~et of microcells, so that these microcells can be at least partially filled through the resulting apertures. Place-ment of the third membrane, if employed, follows the same techniques and considerations as for.the first and second membranes. It is usually preferred that the last set of microcells be opened by the overlying membrane or.mem-branes being~selectively addressed, thereby preserving the ~: closure of the sets of microcell~ previously at least partially filled. ~epending upon the desired application, any membrane(s) remaining after.the last set of microcells bave been ~electi~ely filled to the extent desired can either be left in place, destroyed, or.transferred to a separate support, ~s has been described above.

In an alternative to the processes of differen-tially filling microcells in interlaid sets described above, it is contemplated to place in all of the Micro-cells prior to closu~e by a membrane at least one material that permanently remains in at least one interlaid set of microcells, The membrane closing the microcells is removed by any of the specific techniques described above in all areas, except those corresponding to the set of microcells in which initially present material iB intended to remain. Initially present material i6 then removed from the opened microcells. For example, a soluble material can be removed merely by bringing the element into contact with a solvent, as by spraying with or immer-sion in the solvent. Once at least one set of microcells have been emptied, a second material or combination of materials is placed in the emptied se~ of microcells.
The general procedure described above can be illustrated by reference to forming the multicolor filter element 400. A removable blue filter material, such as a ~0 blue filter dye that can be solubilized is initially introduced into microcells 108 of the support 102. The microcells are then closed with a membrane 502 so that the element appears similar to that of Figure 5A, but with the microcells each containing blue filter material. There-after, the interlaid second and third 6ets of microcellsintended to contain green and red filter materials, respectively, are opened by using any of the ~elective membrane removal techniques described above. Membrane segments similar to 506 now overlie only the microcells in which the filter material is to be retained. The element can be contacted with a solvent for the blue filter mater-ial, permitting it to be removed from the open second and third sets of microcells. The second and third sets of microcells can be now at least partially filled with a green filter material which can be Qolubilized, and the second and third sets of microcells are closed with a ~econd membrane. -The 6e~ments of the first membrane can be first removed or, preferably, left in place, since they do not affect the process. Using an essentially repeti-tive proced~re, the portions of the second membrane over-lying the third set of microcells is 6electively removed, and the green filter material is removed from the third set of microcells. The second membrane remains intact closing tbe first and second sets of microcells, and the blue and green filter materials remain in place in these microcells. Red filter material can now be introduced into the third set of microcells.
It is to be noted that, since the membranes protect the microcells containing the material desired to be retained, the green and blue microcells can be entirely or only partially filled with material without any varia-tion in the process. It is immaterial whether the red filter material can be solubilized or whether the red filter material entirely or par~ially fills the third set of microcells, since this has no effect on the process steps. Once the third set of microcells are filled to the extent desired, any portion of the membrane left in place can be removed, if desired, dependiog upon the intended application for the element. Since air is an exception-ally good thermal insulator, it is preferred that the microcells be only partially filled with the blue and green filter materials to leave an air gap in the micro-cells separating the filter materials from the membranes;however, if the filter materials are good tbermal insu-lators, the increase in laser energy required in address-ing entirely filled microcells can be tolerated.
In using the multicolor filter element 400 des-cribed above a panchromatic imaging material can be employed as a continuous layer coated on a separate support aod form no part of the filter element, simply being juxtaposed with the filter element during exposure and viewing. In anotber form~ the panchromatic imaging material can form a separate continuous layer coated over the first major surface of the support. In still another variant form, the panchromat~c imaging material can lie in each of the microcells so that the filter materials lie ,"

iS~4 between the imaging material and an exposed radiation source. In a specific preferred form a mordant i8 posi-tioned on the bottom walls of the microcells, and the filter.materials are dyes i~mobilized by the mordant and thereby positioned adjacent the bottom walls of the micro-cells. The imaging material can be blended with the filter.material. Where the imaging material is blended with the filter.material, it is preferred to incorporate a selectively blue responsive imaging material in the micro-cells containing blue filter material, a selectively green,responsive imaging material in the microcells containing green filter material, and a selectively red responsive imaging material in the microcells containing red filter material, The three imaging materials can be introduced along with the filter materials as described above, e~cept that the ima~ing materials should be protected against : inadvertent exposure to actinic radiation.
The use of subtractive primary dyes or.dye pre-cursors in interlaid sets of microcells can be appreciated by reference to Figure 6. A multicolor.image transfer.
photographic element 600 is shown. The transparent sup-port 602, the microcells 608 ! and the lateral walls 610 can be identical to corresponding features in element 400, described above. The microcells contain filter.materials and radiation-sensitive imaging materials as descri~ed :~ above, In addition each of the microcells is provided with a subtractive primary dye precursor.which can be shifted between a mobile and an immobile form either.in its dye or.dye precursor.form. The microcells R, the microcells G, and the microcells B are provided with : mobile cyan, magenta, and yellow dye precursor~, respec-tively. The support 602 together with the contents of the : microcells form an image generating portion of the photo-graphic element. For.purposes of iilustration, the photo-graphic element i5 her.einafter.described in terms of a preferred embodiment in which a red responsive silver.
halide emulsion is present in microcells R, a green responsive silver.halide emulsion is present in microcells ,, G, and a blue responsive silver halide emulsion is present in microcells B, each emulsion be;ng blended with an ~ddi-tive primary filter material and a comple~entary subtrac-tive primary dye precu~sor.
An image-receiving portion of the photographic element is comprised of a transparent support (or.cover sheet) 650 on which is coated a conventional dye immobi-li2ing layer 652. A reflection and spacing layer.654, which is preferably white, is coated over the immobilizing layer. A silver.reception layer 656, which contains a silver precipitating agent, overlies the reflection and spacing layer.
In a preferred, integral construction of the photographic element the image-generating and image-receiving portions are joined along their.edges and lie inface-to-face relationship. After imagewise exposure a processing solution is released from a rupturable pod, not shown, integrally joined to the image-generating and receiving portions along one edge thereof. A space 658 is indicated between the image-generating and receiving por-tions to indicate the location of the processing solution when present after exposure. The processing solution contains a silver halide 601vent. A silver.halide devel-oping agent is contained in either.the processing solution or in a position contacted ~y the processing solution upon its release from the rupturable pod. The developing agent or.agents can be incorporated in the silver.halide emul-sions.
The photographic element 600 is preferably a positive-working image transfer system and is described by reference to such a system. In such a system the silver.
halide emulsions are preferably negative-working and the dye precursors are positive-working, altbough direct-posi-tive emulsions and negative-working dye precursors also produce 8 positive-working image transfer.system.
The photographic element 600 is imagewise exposed through the transparent support 602. The red, green and blue filters do not interfere with imagewise exposure, since they a~sorb in each instance primarily only outside that portion of the spectrum to which the emulsion with which they are associated is sensitized. The filters can, however, perform a useful function in protecting the emul-sions from exposure outside the intended portion of thespectrum, For instance, where the emulsions exhibit substantial native blue sensitivity, the red and green filters can be relied upon to absorb light so that the red- and green-sensitized emulsions are not imaged by blue light.
Upon release of processing solution between the image-forming and receiving portions of the element, sil-ver halide development is initiated in the microcells con-taining exposed silver halide. Silver halide development within a microcell results in one exemplary form in a selective immobilization of the initially mobile dye pre-cursor.present, In a preferred form the dye precursor is both immobilized and converted to a subtractive primary dye of a hue complementary to the filter. The residual mobile imaging dye precursor~ either.in the form of a dye or.a precursor, migrates through the silver reception layer.656 and the reflection and spacing layer 654 to the dye immobilizing layer.652. In passing throu~h:the silver.
reception and spacing layers the mobile subtractive pri-mary dyes or precursors are free to and do spread later_ally. Referring to Figure 4A, it can be seen that each : microcell containing a selected subtractive primary dye precursor.is surrounded by microcells containing pre-cursors of the remaining two subtractlve primary dyes. It can thus be seen that lateral spreading results in over-:~ lapping transferred dye areas in the dye immobilizing layer.of the receiver when mobile dye or.precursor is :being transferred from adjacent microcells. Where three subtractive primary dyes overlap in the receiver, black imsge areas are formed, and where no dye iR present, whiteareas are viewed due to the reflection f~om the spacing layer. Where two of the subtrsctive primary dyes overlap at the receiver an additive primary image area is pro-..

, duced. Thus, i~ can be seen that a positive multicolor dye image can be formed which can be viewed through the transparent support 650. The positive multicolor.trans-ferred dye image so viewed is right-reading.
In the multicolor photographic element 600 the risk of undesirable interimage effects attributable to wandering oxidized developing agent is substantially reduced, as compared to conventional multicolor.photogra-phic elements having superimposed color_forming layer units since the lateral walls of the support element prevent direct lateral migration between adjacent reaction microcells. Nevertheless, the oxidized developing agent in some systems can be mobile and can migrate with the mobile dye or.dye precursor toward the receiver.to migrate back to an adjacent microcell. To minimize unwanted dye or.dye precursor immobilization prior to its transfer to the mordant layer.of the receiver it is preferred to incorporate in the silver reception layer 656 a conven-tional oxidized developing agent scavenger.
Since the processing solution contains silver.
halide solvent, the residual silver halide not developed in the microcells is solubilized and allowed to diffuse to the adjacent silver reception layer. The dissolved silver, is physically developed in the silver,reception layer.
Solubilization and trAnsfer.of the silver.halide from the : : microcells operates to limit dire~t or.chemical develop-:ment of silver halide occurring therein. It is well recognized by those skilled in the art that extended con-tact between silver.halide and a developing agent under.
development conditions (e.g., at an alkaline pH) can result in an increase in fog levels. By solubilizing and ; transferring the silver.halide a mechanism is provided for.
terminating silver.halide development in the microcells.
: ~In this way productio~ of oxidized developing agent is terminated and immobilization of dye in the microcells is also terminated. Thus, a very simple mechanism is pro-vided for.terminating silver.halide development and dye immobilization.

-ln a~dition to obtaining a viewable transferred multicolor posi~ive dye ~ma~e a useful negative multicolor dye image is obtained. In microcells where silver.halide development has occurred an immobilized subtractive pri-mary dye is present. This immobilized imaging dye to-gether.with the additive pri~ary filter.offer~ a sub-stantial absorption throughout the visible spectrum, thereby providing a high neutral density to these micro-cells. For.example, where an immobilized cyan dye is formed in a microcell also containing a red filter, it is apparent that the cyan dye absorbs red light while the red filter absorbs in the blue and the green regions of the spectrum. The developed silver present in the microcell also increases the neutral density. In microcells in which silver halide development has not occurred, the mobile dye precursor, either.before or:after conversion to a dye, has migrated to the receiver~ The sole color.
present then is that provided by the filter. It is a distinct advantage in reducing minimum density to employ 2~ the silver reception layer 656 to terminate silver halide development as described above rather.than to rely on other.development termination alternatives. If the image-generating portion of the photographic element 600 is ~:separated from the image-receiving portion, it is apparent that the image-generating portion forms in itself an addi-tiv:e primary multicolor.negative of the exposure image.
: ~ The additive primary negative image can be used for.either.
transmission or.reflection printing to form right-reading multlcolor positive images, such as enlargements, prints and transparencies, by conventional photographic tech-niques, ~: The fore~oing description of photographic element : 600 illustrates the use of initially mobile subtractive ~ primary dye precursors in addition to additive primary :~: 35 filter.materials and red,:green, and blue responsive sil-ver.halide emulsions in interlaid sets of microcells. In alternative multicolor.image ~ransfer.photographic ele-ments the microcells can contain the silver.halide preci-..

- .

pitating agent in the microcells and 8 single panchromsti-cally sensitized silver halide emulsion can be co~ted to overlie the othe~ co~tents of the microcells, either in or above the ~ioroee~ls, The subtractive primary dye pre-cursors can either be initially mobile or immobile.Further, either mobile or immobile subtractive pri~ary dyes capable of undergoing imagewise alterations in mobility can be substituted for the dye precursors. In this instance it is preferred to locate ~he subtractive primary dyes in the microcells so that exposing radiation strikes the silver halide before ~he dye, thereby avoiding competing absorption and any resulting decrease in speed.
In still another variant form preformed image dyes can be shifted in hue so that they do not compete with silver halide in absorbing light to which silver halide in the same microcell is responsive. The dyes can shif~ back to their desired image huè upon contact with processing solu-tion. If no additive multicolor retained image is desired, the additive primary filter materials can be omitted from the microcells in those instances where the silver halide in each set of microcells is responsive to only one of the blue, green, and red portions of the spec-trum. If no transferred multicolor,dye image is desired, the layer 656 can be substituted for,the layer 652 so that a transferred silver image can be viewed while all sub-tractive primary dyes or dye precursor6 can be omitted.
Of course, if no transferred dye or,silver image is desired, the entir~ image receiving portion of the photo-graphic element as well as the subtractive primary dye or, dye precursor can be omitted. It is therefore apparent that a wide variety of different materials can be employed to form interlaid sets of microcells useful in even a specific applicfltiont such as multicolor photography.
Specific illu6t~tion~ o~ preferred multicolor,image transfer,systems that can be ~n~ed according to the present invention are set forth below.
In one specific, illustrative form the photogra-phic element 600 can contain (1) in a first set of micro-1;~6~SQ4-25-cells a blue filter dye or pigment and sn initially color-less, mobile yellow dye-forming coupler, (2) in a second, interlaid set of microcells a green filter.dye or.pigment and an initially colorless, mobile magenta dye-forming coupler.and (3) in a third, interlaid set of microcells a red filter.dye or pigment and an initially colorless, mobile cyan dye-forming coupler. In a preferred for~ a panchromatically sensitized negative-working silver halide emulsion (not shown in Figure 6) is coated over.the micro-cells. The layer 656 contains a silver.precipitatingagent and an oxidized developing agent scavenger~ The reflection and spacing layer.654 can be a conventional titanium oxide pigment containing layer. The dye immobi-lizing layer.652 contains a substantially immobile oxidiz-ing agent.
The photographic element 600 so constituted isfirst exposed imagewise through the transparent support 602. Thereafter.a- processing composition containing a color.developing agent and a silver halide solvent is released and uniformly spread in the space 65B. In exposed areas silver halide is developed producing oxi-dized color.developing agent which couples with the dye ~:: forming coupler.present to form an immobile dye. The ~ filter dye or.pigment, the immobile dye formed, and the : 25 developed silver.thus together increase the optical density of the microcells which are exposed.
In areas not exposed, the undeveloped silver halide is solubilized by:the silver.halide solvent and migrates to the layer 6~56 where it is reduced to silver.
Any oxidized developing agent produced in reducing the silver.halide to ~ilver.immediately cross-oxidizes with : the oxidized developing agent scavenger.which is present :~ with the silver.precipitating agent in the layer.656.
ht the same ti~e mobile coupler.is wandering from microcells which were not exposed. The mobile coupler does not react with oxidized color.developing agent in the layer 656, since a~y oxidized color.developiog agent present preferentially reacts with the ~cavenger. The coupler thus migrates through layer 656 unaffected and enters reflection and spreading layer 654. Because of the thickne~ss of this layer, the mobile coupler is free to wander laterally to some extent. Upon reaching the immobilizing layer 652, the coupler reacts with oxidized color developing agent. The oxidized color developing agent is produced uniformly in this layer by interaction of oxidizing agent with the color developing agent. Due to lateral diffusion in the spreading layer, superimposed immobile yellow, magenta, and cyan dye images are formed in the immobilizing layer and can be viewed as a multi-color image through the transparent support (or cover sheet) 650 with the layer 654 providing a white reflective background. At the same time, since only filter dye or pigment remains in the unexposed microcells, a useable additive primary negative transparency is formed by the support 602.
To illustrate a variant system, a photographic element as described immediately above can be modified by substituting for the initially colorless, mobile dye form-ing couplers initially mobile dye developers. The dye developers are shifted in hue, so that the dye developer present in the microcells containing red, green, and blue filters do not initially absorb light in the red, green, and blue regions of the spectrum, respectively. A dye mordant as well as an oxidant can be present in the dye immobilizing layer 652. Since the dye image forming material is itself a silver halide developing agent, a conventional activator solution can be employed (prefer-ab~y containing an electron transfer agent). The remain-ing features can be identical to those described in the preceding embodiment.
Upon imagewise exposure and release of the activator solution, dye developer reacts with exposed silver halide to form an immobile subtractive primary dye which is a complemen~ of tbe ndditive primary filter material in the exposed microcell. Thus the optical density of exposed microcells is increased, and a negative 1:~6~;50~

multicolor additive primary image can be formed in the support 602 by the filter materials~ Silver halide devel-opment is terminated by transfer of solubilized silver halide as ~as already been described, In unexposed areas unoxidized dye developer migrates to the immobilizing layer.652 where it is immobilized to form a multicolor positive image. During processing the dye developers shift in hue so that they form subtractive primaries complementary in hue to the additive primary filter.
materials with which they are initially associated in the microcells. That is, the red, green and blue filter.
material containing microcells contain dye developers which ultimately form cyan, magenta and yellow image dyes. Hue shifts can be brought about by the higher pH of processing, mordanting or.by associating the image dye in the receiver with a chelating material.
Instead of using shifted dye developers as described above, initially mobile leuco dyes can be employed in combination with electron transfer.agents to produce essentially similar.results. Since the leuco dyes are initially colorless, hue shifting does not have to be undertaken to avoid competing light absorption during image~ise exposure. The leuco dyes are converted to sub-tractive primary imaging dyes upon oxidation in the dye ~25 immobilizing layer.
: Instead of employing initially mobile dyes or dye : precursor~ as described above, it is possible to employ initially immobile materials, In one specific preferred form benzisoxazolone precursor~ of hydroxylamine dye-releasing compounds are employed. Upon cross-oxidation in the microcells with oxidized electron transfer agent pro-duced by development of exposed silver.halide, release of mobile dye i~ prevented, In areas in which silver.halide i6 not exposed and no oxidized electron transfer.agent is produced mobile dye release occurs. The dye image provid-in8 compounds are preferably initially shifted in hue to avoid competing absorption during imagewise exposure.
Mordant immobilizes the dyes in the layer.652. No oxidant . ~ .

. . .
' :

. ' ' is required in this layer in this embodiment. Except as indicated, this element and its function is similar to the illustrative embodiments deficribed above.
Each of the illustrative embodiments described above employ positive-working dye image providing com-pounds. To illustrate a specific embodiment employing negative-working dye image providing compounds, a first set of microcells 608 can contain a blue filter.dye or pigment, a silver precipitating agent and a redox dye-releaser containing a yellow dye which is shifted in hueto avoid adsorption in the blue region of the spectrum prior to processing . In like manner.a second, interlaid set of microcells contain a green filter dye or.pigment, the silver precipitating agent and a redox dye-releaser containing a analogously shifted magenta dye, and a third, interlaid set of microcells containing a red filter dye Or pigment, the silver.precipitating agent, and a redox dye-releaser containing an analogously shifted cyan dye. The microcells are overcoated with a panchromatically sensi-tized silver,halide emulsion layer containing an oxidizeddeveloping agent scavenger.(not shown in Figure 6). The silver precipitating layer,656 shown in Figure 6 is not present. The reflection and spreading layer is a white titanium oxide pigment layer. The dye immobilizing layer 652 contains a mordant.
The photographic element is imagewise exposed through the transparent support 602. A processing solu-tion containing an electron transfer.agent and a silver halide solvent is spread between the image generating and the image receiving portions of the element. In a pre-ferred form the pH of the processing solution causes the redox dye-releasers to shift to their desired image-form-ing hues. ~n areas in which ~ilver halide is exposed oxidized electron transfer.agent produced by development of exposed silver.halide immediately cros6-oxidizes with the scavenger. Thus, in mierocells corresponding to : exposed silver.halide the redox dye-releasers remain unaltered in their.initially immobile form. In areas in which silver halide is not exposed, silver halide solvent present in the processing solution solubilizes ~ilver halide allowing it to form soluble silver ion complexes (e.g., AgS203-) capable of wandering into the underlying microcells. In the microcells physical development of solubilized silver halide occurs producing silver and oxidized electron transfer agent. The oxidized electron transfer agent interacts with the redox dye-releaser to release mobile dye which is transferred to the layer 652 and immobilized by the mordant. A multicolor positive transferred image is produced in the layer 652 comprised of yellow, magenta, and cyan transferred dyes.
A multicolor positive retained image can also be produced, since (1) the silver density produced by chemical develop-ment in the emulsion layer is small compared to the silverdensity produced by physical development in the microcells and (2) with the image generating portion separated from the image receiving portion the redox dye-releasers remaining in their initial, immobile condition in the microcells can be uniformly reacted with an oxidizing agent to release mobile dye whic~ can be removed from the microcells by washing.
One function of the microcells when provided in photographic elements is to limit lateral image spread-ing- The degree to which it is desirable to limit lateral image spreading will depend upon the photographic applica-tion. Where a photographic image is to be viewed without enlargement and minimal visible graininess is desired, microcells having widths within the range of from about 1 to 200 microns, preferably from about 4 to 100 microns, are contemplated for use in the practice of this inven-tion. To the exten~ ~hat visible graininess can be tolerated for specific photographic applications, the microcells can be still larger in width. W~ere the photo-graphic images produced are intend~d for enlargement,microcell widths in the lower portion of the width ranges are preferred. It is accordingly preferred that the microcells be about 20 microns or less in width where enlargements are to be made of the images produced by 4, '' microcellular imaging. Where the microcells of the support are intended to be filled with a radiation~sensi-tive material to perform an imaging function, the lower limit on the size of the microcells is a function of the photographic speed desired. As the areal extent of the microcells is decreased, the probability of an imaging amount of radiation striking a particular microcell on exposure is reduced. Microcell widths of at least about 7 microns, preferably at least 8 microns, optimally at least 10 microns, are contemplated where the microcells contain radiation-sensitive materials of camera speed. At widths below 7 microns, silver halide emulsions in the microcells can ~e expected to show significant reductions in speed.
The microcells can be of any necessary depth to contain the materials intended to be placed therein. It is generally preferred that the microcells be sized so that they are entirely filled, although in some forms of the invention partial filling of the microcells is contem-plated. In terms of actual dimensions, the depth of the ~0 microcells is chosen as a function of the materials to be placed therein. For example, in photographic applications the depth of the microcells is chosen to permit the material contained therein to provide a desired vptical density. The depths of tke microcells can be less than, equal to, or greater than their width. For photographic applications the depth of the microcells is typically chosen to correspond to the thickness to which the same materials are coated on planar supports. It is ~enerally contemplated that the~depth of the microcells will fall within the range of from a~out 1 to 1000 microns. For silver halide emulsions, dyes, and dye image forming components commonly employed in conjunction with silver halide emulsions, it i~ generally preferred that the microcells be in the range o from 5 to 20 microns in depth.
The spacing between microcells can be varied, depending upon the application and the effect intended.
It is generally preferred for the practice of this inven-SO~

tion that the microcells be laterally spaced from a~out 0.5 to 5 microns, although both greater and less spacings are contemplated. The microcells for photographic appli-cations occupy at least 50 percent ~preferably 80 percent) of the array area. The microcells can, when closely spaced, occupy as much as 99 percent of the array area, but more typically in the practice of this invention occupy no more than 90 percent of the array area.
The supports can be formed of the same types of materials employed in forming conventional photographic supports. Typical photographic supports include polymeric film, and wood fiber--e.g., paper supporting elements provided with one or more subbing layer to enhance the adhesive, antistatic, dimensional, abrasive, hardness, frictional, antihalation and/or other proper~ies of the support surface.
Typical of useful polymeric film supports are films of cellulose nitrate and cellulose esters such as cellulose triacetate and diacetate, polystyrene, poly-amides, homo- and co-polymer~ of vinyl chloride, poly-(vinyl acetal), polycarbonate, homo- and co-polymers of olefins, such as polyethylene and polypropylene, and poly-esters of dibasic aromatic carboxylic acids with divalent alcohols, such as poly(ethylene terephthalate).
Typical of useful paper supports are those which are partially acetylated or coated with baryta and/or a polyolefin, particularly a polymer of an ~-olefin con-taining 2 to 10 carbon atoms, such as polyethylene, poly-propylene, copolymers of ethylene and propylene and the like.
Polyolefins, such as polyethylene, polypropylene and polyallomers--e.g., copoly~ers of ethylene with propylene, as illustrated by Hagemeyer et al U.S. Patent

3,47B,128, are preferably employed as resin coatings over paper~ as illustrated by Crawford et al U.S. Patent 3,411,908 and Joseph et al U.S. Patent 3,630,740, over polystyrene and polyester film supports, as illustrated by Crawford et al U.S. Patent 3,630,742, or can be employed as unitary flexi~le reflection supports, as illustrated by Venor et al U.S. Patent 3,973,963.
Preferred cellulose ester.supports are cellulose ~riacetate supports, as illustrated by Fordyce et al U.S.
Patents 2,492,977, '978 and 2,739,069, as well as mixed cellulose ester supports, such as cellulose acetate propionate and cellulose acetate butyrate, as illustrated by Fordyce et al U.S. Patent 2,739,070.
Preferred polyester film supports are comprised of linear polyester, such as illustrated by Alles et al U.S. Patent 2,627,088, Wellman U.S. Patent 2,720,503, Alles U.S. Patent 2,779,684 and Kibler et al U.S. Patent 2,901,466. Polyester films can be formed by varied tech-niques, as illustrated by Alles, cited above, Czerkas et al U.S. Patent 3,663,683 and Williams et al U.S. Patent 3,504,075, and modified for use as photographic film suppor~s, as illustrated by Van Stappen U.S. Patent 3,227,~76, Nadeau et al U.S. Patent 3,501,301, Reedy et al U.S. Patent 3,589,905, Babbitt et al U.S. Patent 3,850,640, Bailey et al U.S. Patent 3,888,678, Hunter.U.S.
Patent 3,904,420 and Mallinson et al U.S. Patent 3,928,697.
Supports which are resistant to dimensional change at elevated temperatures can be formed. Such supports can be comprised of linear condensation polymers which have glass transition temperatures above about 190C, preferably 220CI such as polycarbonates, poly-carboxylic esters, polyamides, polysulfonamides, poly-ethers, polyimides, polysulfonates and copolymer.variants, as illustrated by Hamb U.S. Patents 3,634,089 and 3,772,405; Hamb et al U.S. Patents 3,725,070 and 3,793,249; Gottermeier.U.S. Patent 4,076,532; Wilson Researcb i8_ losure, Vol. 118, February 1974, Item 11833, and Vol. 120, April 1974, Item 12046; Conklin et al Research Disc~osure, Vol. 12Q, April 1974, Item 12012;
Product Licensing Index, Vol. ~2, De~ember 1971, Items 9205 and 9207; Research Disclosure, Vol. 101, September.
1972, Items 10119 and 10148; Research Disclosure, Vol.
106, February 1973, Item 10613; Research Disclosure, Vol.
:, 117, January 1~74, Item 1~7~, and Reeearch Disclosure, Vol. 134, June 1975, Item 13455. Research Disclosure is published by Industrial Opportunities Ltdo~ Homewell, Havant Hampshire, PO9 lEF, UK.
The second support elements which define the lateral walls of the microcells can be selected from a variety of materials lacking sufficient structural strength to be employed alone as supportsO It is specifi-cally contemplated that the second support elements can be formed using conventional photopolymerizable or photo-crosslinkable materials--e.g., photoresists. Exemplary conventional photoresists are disclosed by Arcesi et al U.S. Patents 3,640,722 and 3,748,132, Reynolds et al U.S.
patents 3,696,072 and 3,748,131, Jenkins et al U.S.
Patents 3,699,025 and '026, Borden U.S. Patent 3,737,319, Noonan et al U.S. Patent 3,74~,133, Wadsworth et al U.S.
Patent 3,779,989, DeBoer U.S~ Patent 3,782,938, and Wilson U.S. Patent 4,052,367. Still other useful photopolymeriz-able and photocrosslinkable materials are disclosed by Kosar, Light-Sensitive Systems Chemistry and Application of Nonsilver Halide Photo~raphic Processes, Chapters 4 and 5, John Wiley and Sons, 1965. It is also contemplated that the second support elements can be formed using radiation-responsive colloid compositions, such as di-chromated colloids--e.g., dichromated gelatin, as illus-trated by Chapter 2, Kosar, cited above. The second support elements can also be formed using silver halide emulsions and processing in the presence of transition metal ion complexes, as illustrated by Bissonette U.S.
Patent 3,856,524 and McGuckin U.S. Patent 3,862,855. The advantage of using radiation-sensitive materials to form the second support elements is that the lateral walls and microcells can be simultaneously defined by patterned exposure~ ODC~ formed the second support elements are not themselves further respon~ive to exposin~ radiation.
It is contemplated that the second support ele-ments can alternatively be formed of materials commonly employed as vehicles and/or binders in radiation-s2nsitive ~. ~

l:lti~S(~

materials. The advantage of using vehicle or binder materials is their known compatibility with radiatlon-sensitive materials that may be used to fill the micro-cells. The b~nders and/or vehicles can be polymerized or hardened to a somewhat higher degree than when employed in radiation-sensitive materials to insure dimensional integrity of the lateral walls which they form. Illustra-tive of specific binder and vehicle materials are those employed in silver halide emulsions, typically gelatin, gelatio derivatives, and other hydrophilic colloids.
Specific binders and vehicles are disclosed in Research Disclosure, Vol. 1786, December 1978, Item 17643.
The light transmission, absorption and reflection qualities of the supports can be varied for different applications. The supports can be substantially trans-parent or reflective, preferably white, as are the majority of conventional photographic supports. The supports can be reflective, such as by mirroring the microcell walls. The supports can in some applications contain dyes or pigments to render them substantially light impenetrable. Levels of dye or pigment incorpora-tion can be chosen to retain the light transmis~ion characteristics in the thinner regions of the supports ~-e.g., in the microcell bottom wall region-- while rendering the supports relatively less light penetrable in thicker region --e.g., in the lateral wall regions between adjacent microcells. The supports can contain neutral colorant or colorant combinations. Alternatively, the ; supports can contain radiation absorbing materials which are ~elective to a singl~ region of the electromagnetic spectrum --e.g., blue dyes. The supports can contain materials which alter radiation transmi~sion qualities, but are not visible, such as ul~raviolet absorbers. Where two supports are employed in combination, the light trans-mission~ ab~orption and reflection qualities o$ the twosupports ca~ be the same or different, depending upon the intended application.

S~

W~ere the ~upports are formed of conventional photograp~ic suppor~ materials, they can be provided with reflective and absorbing materials by techniques well known by those skilled in the art, such techniques being adequately illustrated in the various patents cited above in relation to support materials. In addition, reflective and absorbing materials can be employed of varied types conventionally incorporated directly in radiation-sensi-tive materials, particularly in second supports formed of vehicle snd/or binder materials or using photoresists or dichromated gelatin. The incorporation of pigments of high reflection index in vehicle materials is illustrated, for example, by Marriage U.K. Patent 504,283 and Yutzy et al U.K. Patent 760,775. Absorbing materials incorporated in vehicle materials are illustrated by Jelley et al U.S.
Patent 2,697,037; colloidal silver (e.g., Carey Lea Silver widely used as a filter for bIue light); super fine silver halide used to improve sharpness, as illustrated by U.K.
patent 1,342,687; finely divided carbon used to improve sharpness or for antihalation protection, as illustrated by Simmons U.S. Patent 29327,828; filter and antihalation dyes, such as the pyrazolone oxonol dyes of Gaspar U.S.
Patent 2,274,782, the solubilized diaryl azo dyes of Van Campen U.S. Patent 2,956,879, the solubilized styryl and butadienyl dyes of Heseltine et al U.S. Patents 3,423,207 and 3,384,487, the merocyanine dyes of Silberstein et al U.S. Patent 2,527,583, the merocyanine and oxonol dyes of Oliver U.S. Patents 3,486,897 and 3,652,284 and Oliver et aI U.S. Patent 3,718,472 and the enamino hemioxonol dyes of Brooker et al U.S. Patent 3,976,661 and ultraviolet absorbers, such as the cyanomethyl sulfone-derived mero-cyanines of Oliver U.S. Patent ~,723,154, the thiazoli-dones, benzotriazoles and thiazolothiazolefi of Sawdey U.S.
Patents 2,739~888, 3,253,921 and 3,250,617 and Sawdey et al U.S. Patent 2,739,~7~, the triazoles of Heller et al U.S. Patent 3,004,896 and the hemioxonols of Wahl et al U.S. Patent 3,125,597 and Weber et al U.S. Patent

4,045,229. The dyes and ultraviolet absorb2r~ can be - .

.

- \
;S04 mordanted, as illustrated by Jone~ et al U.S. Patent 3,282,699 and Heselti~e et al ~.S. Patents 3,455,693 and 3,438,779.
One preferred technique according to this inven-tion for preparing microcell containing supports is toexpose a photographic element having a transparent support in a regular hexagonal pattern, such as illustrated in Figure lA. In a preferred form the photographic element is negative-working and exposure corresponds to the areas intended to be subtended by the microcell areas while the areas intended to be subtended by the lateral walls are not exposed. By conventional photographic techniques a pattern is formed in the element in which the areas to be subtended by the microcells are of a substantially uniform maximum density while the areas intended to be subtended by the lateral walls are of a substantially uniform mini-mum density.
The photographic element bearing the image pattern is next coated with a radiation-sensitive composi-tion capable of forming the lateral walls of the supportand thereby defining the side walls of the microcells. In a preferred form the radiation-sensitive coating is a negative-working photoresist or dichromated gelatin coat-ing. The coating can be on the urface of the photogra-phic element bearing the image pattern or on the oppositesurface-_e.g., for a silver halide photographic element, the photoresist or dichromated gelatin can be coated on the support or emulsion side of the element. The photo-resist or dichromated gelatin coating is next exposed through the pattern in the photographic element, so that the areas corresponding to the intended lateral walls are exposed. This results in hardening to form the lateral wall structure and allowing the unexposed material to be removed according to conventional procedures well known to those ~iL~ed in the art. For instance, these procedures are fully described in tbe patents cited above in connec-tion with the description of photoresist and dichromated gelatin support materials.

The image pattern is preferably removed before the element is subsequently put to use. For example, where a silver halide photographic element is exposed and processed to form a silver image pattern, t~e silver can be bleached by con~entional photographic techniques after the microcell structure is formed by the radiation-sensi-tive material.
If a positive-working photoresist is employed, it is initially in a hardened form, but is rendered selec-tively removable in areas which receive exposure. Accord-ingly, witb a positive-working photoresist or other radia-tion-sensitive material the sense of the exposure pattern is reversed. If an exposure blocking pattern is present in or on the support corresponding to the lateral walls forming the microcells, this pattern need not be removed for many applications and can even take the place of increasing the optical density of the lateral walis forming the microcells in many instances. Instead of coating tbe radiation-sensitive ~aterial onto a support bearing an image pattern, such as an image-bearing photo-graphic element, the radiation-sensitive material can be coated onto any conventional support and imagewise exposed directly rather than througb an image pattern. It is, of course, a simple matter to draw the desired microcell pattern on an enlarged or macro-scale and then to photo-reduce the pattern to the desired scale of the microcells or purposes of exposing the photoresist.
Another technique which can be used to form the microcells in the support is to form a plastic deformable material as a planar element or as a coating on a rela-tively nondeformable support element and then to form the microcells in the relatively deformable material by embossing. An embossing tool i8 employed which contains projectioos corresponding to th~ desired ~hape of the microcells. The proJections can be formed on an initially plane surface by conventional techniques, such as coating the surface with a photoresist, imagewise exposing in a desired pattern and removing the photoresist in the areas corresponding to the spaces between the inte~ded projec-tions (which also correspond to ~he configuration of the lateral walls to be formed in the support). The areas of the embossing tool surface which are not protected by photoresist are then etched to leave the projections.
Upon removal of the photoresist overlying the projections and any desired cleaning step, such as washing with a mild acid, base or other solvent, the embossing tool is ready for use. In a preferred form the embossing tool is formed of a metal, such as copper, and is given a metal coating, such as by vacuum vapor depositing chromium or silver.
The metal coating results in smoother walls being formed during embossing.
The foregoing techniques are well suited to form-ing transparent microcell containing supports, a vsriety of transparent materials being available ~atisfying the requirements for use. Where a white support is desired, white materials can be employed or the transparent materi-als can be loaded with white pigment, such as titania, baryta and the like. Any of the whitening materials employed in conjunction with conventional reflective photographic supports can be Pmployed. Pigments to impart colors other than white to the support can, of course, also be employed, if desired. Pigments are particularly well suited to forming opaque supports which are white or colored. Where it is desired that the support be trans-parent, but tinted, dyes of a conventional nature are preferably incorporated in the support for~ing materials.
For example, in one form of the support described above the support is preferably yellow to absorb blue light while tran~mitting red and green.
In various forms of the supports described above the portion ~f the support forming the bottom walls of at least one ~et of microcell~, generally all of the micro-cells, is transparent, and the port~on o the æupport forming the lateral walls is either opaque or dyed to intercept light transmission therethrough~ As has been -3g discu~sed above, one technique for achieving this result is to employ different support materials to form the bottom and later~ walls of the supports.
A preferred technique for achieving dyed lateral walls and transparent bottom walls in a support formed of a single material is as follows: A transparent film is employed which is initially unembossed and relatively non-deformable with an embossing tool. Any of the transparent film-forming materials more specifically described above and known to be useful in forming conventional photo-graphic film supports, such as cellulose nitrate or ester, polyethylene, polystyrene, poly(etbylene terephthalate) and similar polymeric films, can be employed. One or a combination of dyes capable of imparting tbe desired color to the lateral walls to be formed is dissolved in a solu-tion capable of softening the transparent film. The solu-tion can be a conventional plasticizing solution for the film. As the plasticizing solution migrates into the film from one major surface, it carries the dye along with it, so that the film is both dyed and softened along one major surface. Thereafter the film can be embossed on its softened and tberefore relatively deformable surface.
This produces microcells in the film support which have dyed lateral walls and transparent bottom walls.
The membranes positioned to close the microcells of the support are comprised of any material which can be selectively destroyed or removed over an area correspond-ing to that subtended by an underlying microcell (or, in some instances, an underlying cluster of microcells). In 3 general the membranes can be most conveniently formed of organic film-forming polymers. The membranes can be identical in composition to conventional photographic film ~upports~ Typical film-fo~ming polymers useful in forming membranes are cellulose nitrate and cellulose esters, such as cellulose triacet~te and diacetate, polyamides, homo-and co-polymers of ~tyrene, acrylates and methacrylates, vinyl chloride, poly(vinyl acetal), and olef~ns, such as ethylene and propylene. Where tbe membranes are intended to be thermally destroyed, as by impingement with a laser beam, the less thermally stable film-forming polymers used in preparing photographic film 6upports are preferred.
Merely heating the membranes to their thermal decomposi-tion temperature is not, however, the only way of destroy-ing the membranes. Cellulose coatings and particularly cellulose nitrate can be selectively destroyed in exposed areas by alpha particles and similar fu~ion fragments, as taught by Sherwood U.S. Patent 3,501,636. It is also specifically contemplated to employ electron beams to destroy the membrane in selected areas.
Generally any conventional combination of materi-als known to be useful when related in an interlaid pattern can be selected for incorporation in the separate sets of microcells. Virtually any known additive primary dye or pigment can, if desired, be selected for use in the multicolor filters descr~bed above. Further, the additive primary color can be lmparted by blending two subtractive primary dyes or pigments. Additive and subtractive pri-mary dyes and pigments mentioned in the Color Index,Volumes I and II, 2nd Edition, are generally useful in the practice of at least one form of the present invention.
For photographic applications it has been recog-nlzed that the incorporation of radiation-~en~itive and/or imaging forming materials in microcells has the effect of limiting lateral image spreading. Lateral image 6preading has been observed in a wide variety of conventional photo-graphic elements. Lateral image spread can be a product of optical phenomena, such as reflection or scattering of expos~ng radiation; diffu6ion phenomena, such as lateral diffusion of radiation-sensit~ve and/or imaging materials in the radiation-sen6itive and/or imaging layers of the photographic elements; or, most commonly, a combination of both. Lateral image spreading is particularly common where the radiation-6ensi~ive and/or other imaging materi-als are dlspersed in a vehicle or binder intended to be penetrated by exposing radiation and/or processing . ~, fluids. While the present invention can be practiced with - conventional radiation-sensitive and image-forming materi-als known to be useful in photography 9 i~ i3 appreciated that materials which exhibit visu~lly detectable lateral image spreading are part$cularly benefited by incorpora-tion into microcells according to this invention.
A variety of useful nonsilver lmaging materials useful in the practice of this invention are di~closed by Kosar, Light-Sensitive Sys~ems: Chemistry and Application of Nonsilver Halide Photo~raphic Processes, John Wiley and Sons, 1965. Generally any imaging system capable of form-ing a multicolor image can be applied to the practice of this inventlon. It is specifically preferred to employ in the practice of this invention, radiation-sensitive sllver halide and the image forming materials associated there-with in multicolor imaging. Exemplary materials are des-cribed in Research Disclosure, Vol. 176, December 1978, Item 17643. Particularly pertinent are paragraphs I.
Emulsion types, III. Chemical æensitization 7 IV. Spectr~l sensitization, VI. Antlfoggan~s and stabilizerA, IX.
Vehicles, and X. Hardener~, which set out conventional features almost always present in preferred silver halide emulsions useful in the practice of this inven~ion.
A variety of dye image transfer systems have been developed and can be employed in the practice of this invention. One approach is to employ ballasted dye-form-ing (chromogenic) or nondye-forming ~nonchromogenic) couplers having A mobile dye attached at a coupling-off site. Upon coupling with an oxidized color developing agent, such as a para-phenylenediamine, the mobile dye is displaced 80 that it can transfer to a receiver. The use of such negative-working dye image providing compounds is illustrated by Whitmore et al U.S. Patent 3,227,550, Whitmore U.S. Patent 3,227,552 ~nd Fu~iwhara et al U.K.
Patent 1,445,797.

In a preferred image transfer system employing as negative-working dye image providing compounds redox dye-releasers, a cross-oxidizing developing agent (electron transfer agent) develops silver halide and then cross-oxi-dizes with a compound containing a dye linked through anoxidizable sulfonamido group, such as a sulfonamidophenol, sulfonamidoaniline, sulfonamidoanilide, sulfonamido-pyrazolobenzimidazole, sulfonamidoindole or sulfGnamido-pyrazole. Following cross-oxidation hydrolytic deamida-tion cleaves the mobile dye with the sulfonamido group attached. Such systems are illustrated by Fleckenstein U.S. Patents 3,928,312 and 4,053,312, Fleckenstein et al U.S. Patent 4,076,529, Melzer et al U.S. Patent 4,110,113, Degauchi U.S. Patent 4,199,892, Koyama et al U.S. Patent 4,055,428, Vetter et al U.S. Patent 4,198,235, and Kestner et al Research Disclosure, Vol. 151, November 1976, Item 15157. Also specifically contemplated are otherwise similar systems which employ an immobile, dye-releasin~
(a) hydroquinone, as illustrated by Gompf et al U.S.
Patent 3,698,897 ~nd Anderson et al U.S. Patent 3,725,062, (b) para-phenylenediamine, as illustrated by Whitmore et al Canadian Patent 602,607, or (c) quaternary ammonium compound, as illustrated by Becker et al U.S. Patent 3,728,113.
Another specifically contemplated dye image transfer æystem which employs negative-working dye image providing compounds reacts an oxidized electron transfer agent or, specifically, in certain forms, an oxidized para-phenylenediamine with a ballasted phenolic coupler having a dye attached through a sulfonamido linkage. Ring closure to form a phenazine releases mobile dye. Such an imaging approach is illustrated by Bloom et al U.S.
Patents 3,443,g39 and 3,443,940.
I~ still another image transfer system employing negative-working dye image providing compounds, ballasted sulfonylamidrazones, sulfonylhydrazones or sulfonyl-carbonylhydrazides can be reacted with oxidized Para-phenylenediamine to release a mobile dye to be trans-s~-4~-ferred, as illustrated by Puschel et al U.S. Patents 3,628,952 and 3,844,785. In an additional negative-work-ing system a hydrazide can be reacted with silver hallde having a developable latent image site and thereafter decompose to release a mobile, transferable dye, as illustrated by Rogers U.S. Patent 3,245,789, Kohara et al Bulletin Chemical Society of Japan, Vol. 43, pp. 2433-37, and Lestina et al Research Disclosure, Vol. 28, December 1974, Item 12832.
The foregoing image transfer systems all employ negative-working dye image providing compounds which are initially immobile and contain a preformed dye which is split off during imaging. The released dye is mobile and can be transferred to a receiver. Positive-working, initially immobile dye image providing compounds which split off mobile dyes are also known. For example, it is known that when silver halide is imagewise developed the residual silver ions associated with the undeveloped silver halide can react with a dye su~stituted ~allasted thiazolidine to release a mobile dye imagewise, as illustrated by Cieciuch et al U.S. Patent 3,719,489 and Rogers U.S. Patent 3,443,941.
Preferred positive-working, initially im~obile dye image providing compounds are those which release mobile dye by intramolecular nucleophilic displacement reactions. The compound in its initial form is hydrolyzed to its active form while silver halide development with an electron transfer agent is occurring. Cross-oxidation of the active dye-releasing compound by the oxidized electron transfer agent prevents intramolecular nucleophilic release of the ~y~ ~oiety. BenziQoxazolone precursors of hydrox~la0ine dye-releaeing compounds are illustrated by Hinshaw et al U.S. Patent 4,199,354, and Research Dis-closure, Vol. 144, April 1976, Item 14447. N-Hydro-quinonyl car~amate dye-releasing compounds are illustrated by Fields et al U.S. Patent 3,980,479. It is also known to employ an immo~ile reducing agent precursor (electron donor precursor) in combination with an immobile ballasted . .

:

1~6tjSO~

elec~ron-accepting nucleophilic displacement (BEND) com-pound which, on reduction, anchimerically dlsplaces a diffusi~le ~ye. Hydrolysis of the electron donor pre-cursor to its active form occurs simultaneously with silver halide development by an electron transfer agent.
~ross-oxidation of the electron donor with the oxidized electron transfer agent prevents further reaction. Cross-oxidation of the BEND compound with the residual, un-oxidized electron donor then occurs. Intramolecular nuc-leophilic displacement of mobile dye from the reduced BENDcompound occurs as part of a ring closure reaction. An image transfer system of this type is illustrated by Chasman et al U.S. Patent 4,139,379.
Other positive-working systems employing ini-tially immobile, dye-releasing compounds are illustrated by Rogers U.S. Patent 3,185,567 and U.K. Patents 8B0,233 and '234.
A variety of positive-working, initially mo~ile dye image providing compounds can ~e imagewise immo~ilized ~y reduction of developa~le silver balide directly or indirectly through an electron transfer agent. Systems which employ mobile dye developers, including shifted dye developers, are illustrated by Rogers U.S. Patents 2j774,668 and 2,983,606, Idelson et al U.S. Patent 3,307,947, Dershowitz et al U.S. Patent 3,230,085, Cieciuch et al U.S. Patent 3,579,334, Yutzy U.S. Patent 2,756,142, Harbison Def. Pub. T889,017, and Bush et al U.S. Patent 3,854,945. In a variant form a dye moiety can ~ be attached to an initially mobile coupler. Oxidation of a para-phenylenediamine or hydroquinone developing agent can result in a reaction between tbe oxidized developing agent and the dye containing a coupler to form an immobile compound. Such systems are illustrated by Rogers U.S.
Patents 2,774,~68 and 3,Q~7,817, Greehalgh et al U.K.
Patents 1,157~5~1-5Q6, Pusc~el et al U.S. Patent 3,844,785, Stewart et al U.S. Patent 3,653,896, Gehin et al French Patent 2,28i,711, and Research Disclosure, Vol.
145, May 1976, Ite~ 14521.

o~

Other ima~e transfer systems employing positive-working dye i~age provid~ng compounds are known in which varied immobiliz~io~ or tran~fer techniques are employ-ed. For example, a mo~i~e developer-mordant can be image-wise immo~ilized ~y development of silver halide to image-wise immobilize an initially mobile dye, as illustrated by Haas U.S. Patent 3,729,314. Silver halide development with an electron transfer agent can produce a free radical intermediate which causes an initially mo~ile dye to poly-merize in an imagewise manner, as illustrated by Pelz etal U.S. Patent 3,585,030 and Oster U.S. Patent 3,019,104.
Tanning development of a gelatino-silver balide emulsion can render the gelatin impermeable to mobile dye and thereby imagewise restrain transfer of mobile dye as illustrated by Land U.S. Patent 2,543,181. Also gas bub~les generated by silver halide development can be used effectively to restrain mobile dye transfer, as illustrat-ed by Rogers U.S. Patent 2,774,668. Electron transfer agent not exhausted by silver halide development can be transferred tO a receiver to imagewise bleach a polymeric dye to a leuco form, as illustrated by Rogers U.S. Patent 3,015,561.
A number of image transfer systems employing positive-working dye image providing compounds are known in which dyes are not initially present, but are formed by reactions occurring in the photographic element or receiver following exposure. For example, mobile coupler :: and color developing agent can be imagewise reacted as a ; function of silver halide development to produce ao immobile dye while ~esidual developing agent and coupler are transferred to the receiver and the developing agent is oxidized to form on coupling ~ transferred immobile dye image, as ill~s~rated by Yutzy U.S. Patent 2,756,142, Greenhalgh et al U.K. Patents 1,157,501-'506l and Land U.S. Patents 2,559,643, 2,647,049, 2,661,293, 2,698,244, and 2,698,798. In a variant form of this system the coupler can be reacted with a solubilized diazonium salt (or azosulfone precursor) to form a diffusible azo dye before transfer, as illustrated by Viro et al U.S. Patent 3,837,852. In another variant form a single, initially mobile coupler-de~elopeT compound can participate in intermolecular self-coupling at the receiver to form an immo~ile dye image, as illustrated by Simon U.S. Patent 3,537,850 and Yoshiniobu U.S. Patent 3,865,593. In still another variant form a mobile amidrazone is present with the mobile coupler and reacts with it at the receiver to form an immobile dye image, 8S illustrated by Janssens et al U.S. Patent 3,939,035. Instead of using a mobile coupler, a mobile leuco dye cao be employed. The leuco dye reacts with oxidized electron ~ransfer agent to form an immobile product, w~ile unreacted leuco dye is trans-ferred to the receiver and oxidized to form a dye image, as illustrated by Lestina et al U.S. Patents 3,880,658, 3,~35,262, and 3,935,263, ~ohler et al U.S. Patent 2,892,710, Corley et al U.S. Patent 2,992,105, and Rogers U.S. Patents 2,909,430 and 3,065,074. Mobile quinone heterocyclammonium salts can be immobilized as a function of silver balide development and residually transferred to a receiver where conversion to a cyanine or merocyanine dye occurs, as illustrated by Bloom U.S. Patents 3,537,851 and '852.
Image transfer systems employing negative-working dye image providing compounds are also known in which dyes are not initially present, but are formed by reactions occurring in the photographic element or receiver follow-ing exposure. For example, a ballasted coupler can react with color developing agent to form a mobile dye, as illustrated by Whitmore et al U~S. Patent 3,227,550, Whitmore U.S. Patent 3,227,552, Bush et al U.S. Patent 3,791, 827, and Viro et al U.S. Patent 4,036,643. An immobile compound containing a coupler can react with oxldized pa~a pbenylenediamine to release a mobile coupler whicb can react witb additional oxidized para-phenylene-diamlne before, during or after release to form a mobile dye, as illustrated by Figuerss et al U.S. Patent 3,734,726 and Janssens et al German OLS 2,317,134. In o~

another ~orm a ~allasted amidrazone reacts wit~ an electron transfer agent as a function of silver halide development to release a mo~ile amidrazone which reacts with a coupler to form a dye at the receiver, as illustrated by Ohyama et al U.S. Patent 3,933,493~
Where oxidation at the receiver is relied upon to produce an immobile transferred dye image, the receiver can contain as a continuous layer or in microvesels an oxidizing agent. Exemplary useful o~idants for such applications include ~orates, persulfates, ferricyanides, periodates, perchlorates, triiodides, permanganates, dichromates, manganese dioxide, silver halides, benzo-quinones, naphthoquinones, disulfides, nitroxyl compounds, heavy metal oxidants, heavy metal oxidant chelates, N-bromo-succinimides, nitroso compounds, ether peroxides, and the like. The oxidants are preferably chosen from among those of sufficient molecular bulk to ~e substan-tially immobile and there~y confined during processing to the receiver. Exemplary preferred im~o~ile oxidants are the immobile nitroxyl compounds disclosed ~y Ciurca et al U.S. Patent 4,088,488. Other useful immobile oxidants can be chosen from among those described in the patents cited a~ove disclosing oxidation at a receiver to form a dye.
Where oxidation does not in itself result in the formation of an immo~ile dye, as where the oxidant's primary ~unc-tion is to form a dye, rather than immobilization, a ` combination of oxidant and a mordant or other immo~ilizing agent can ~e present in the dye image providing layer.
; ~ Mordants employed to immobilize dyes in the practice of this invention can be chosen from a variety of known mordants. Examples of useful mordants include the following: Sprague et al U.S. Patent 2,548,564, Weyerts U.S. Patent 2,548,575, Carroll et al U.S. Patent 2~675~316J Yutzy et al U.S. Patent 2,713,305, Saunders et al U.S. Patent 2,75~,149, Reynolds et al U.S. Patent 2,768,078, Gray et al ~.S. Patent 2,839,401, ~insk U.S.
Patents 2,882,156 and 2,945,006, Whitmore et al U.S.
Patent 2,940,849, Condax U.S. Patent 2,952,566, Mader et - - , , .

al U.S. Patent 3~016,305, Minsk et ~1 U.S. Patents 3,048,487 and 3,184,309, Bush U.S. Patent 3,271,147, Whitmore U.S. Patent 3,271,148, Jones et el U.S. Patent 3,282,699, Wolf et al U.S. Patent 3,408,193, Cohen et al U.S. Patents 3,488,706, 3,557,066, 3,625,694, 3,709,690, 3,758,445, 3,788,855, 3,898,088, and 3,944,424, Cohen U.S.
Patent 3,639,357, Taylor U.S. Patent 3,770,439, Campbell et al U.S. Patent 3,958,995, and Ponticello et al Research Disclosure, Vol. 120, April 1974, Item 12045. Preferred mordants for forming filter layers are more specifically disclosed by Research Disclosure, Vol. 167, March 1978, Item 16725.
Any one of the systems for forming transferred dye images of the patents and publications cited above as illustrating image transfer systems employing po~itlve and negative-working dye image providing compounds can be readily employed in the practice of this invention. Other features of useful dye image transfer systems are set forth in Paragraph XXIII, Item 17643, Research Disclosure, cited above.
The use of silver ion complex precipitating agents is disclosed in connection with various preferred forms of multicolor image transfer element 600. A wide variety of nuclei or silver precipitating agents can be utilized in the reception layers used in silver halide solvent transfer processes. Such nurlei are incorporated into conventional photographic orgenic hydrophilic colloid layers such as gela~in and polyvinyl alcohol layers and include quch physical nuclei or chemical precipitants as (a) heavy metals, especially in colloidal form and salts of these metals, (b) salts, the anions of which form silver salts less ~oluble than the silver halide of the photographic emulsion to be processed, and (c) non-diffusible polymeric materials with functional groups capable of combining with and insolubilizing silver ions.

~J

XO~

Typical useful silver precipitating agents include sulfides, selenides, polysulfides, polyselenides, thiourea and its derivatives, mercaptans, stannous halides, silver, goldt pla~inum, palladium~ me~cury, colloidal silver, aminoguanidine sul~ate, aminoguanidine carbonate, arsenous oxide, sodium stannite, substituted hydrazines, xanthates, and the like. Poly(vinyl mercapto-acetate) is an example of a suitable nondiffusing poly-meric silver precipitate. Heavy metal sulfides 8uch as lead, silver, zinc, aluminum, cadmium, and bismuth sulfides are useful, particularly the sulfides of lead and zinc alone or in an admixture of complex ~alts of these with thioacetamide, dithio-oxamide, or dithiobiuret. The heavy metals and the noble metals, particularly in colloidal form, are especially effective. Other silver precipitating agents will occur to t~ose skilled in the present art.
Useful oxidized developing agent scavengers include ballasted or otherwise nondiffusing (immobile) antioxidants, as illustrated by Weissberger et al U.S.
Patent 2,336,327, Loria et al U.S. Patent 2,728,659, Vittum et al U.S. Patent 2,360,290, Jelley et al U.S.
Patent 2,403,721, and Thirtle et al U.S. Patent 2,701,197. To avoid autooxidation the scavengers can be employed in combination with other antioxldantS, as illustrated by Knechel et al U.S. Patent 3,700,453.

;S~

The invention can be more specifically appreci-ated by reference to the following ill~strative examples:
Example 1 A pattern of hexagons 20 microns in width and approximately 10 microns high was formed on a copper plate by etc~ing. Using the etched plate having hexagon projec-tions, diehloromethane and ethanol (80:20 volume ratio) solvent containing 10 grams per 100 ml of Genacryl Orange-R, a yellow azo dye, was placed in contact with a cellulose acetate photographic film ~upport for ~ix seconds. Hexagonal microcells were embossed in the softened support separated by 2 micron lateral walls, as measured at the surface of the support. The yellow dye was absorbed in the cellulose acetate film support areas laterally surrounding, but not beneath, the microcells, giving a density to blue light.
A membrane was prepared by placing four drops of a commercial casting solution (Microfilm Solutio~ , Sig Manufacturing Company, Montezuma, Iowa) onto the surface of water contained in a 30 by 35 cm tray~ The casting solution contained cellulose nitrate as a film-forming polymer in an organic solvent comprised of aromatic hydro-carbon liquids (toluene and xylene) forming a major component and, as minor components, a mixture of lower molecular weight aliphatic alcohols, esters, and ketones (isopropyl alcohol, methyl ethyl ketone, 2-methyl propanol, isopropyl acetate, and methyl isobutyl ketone).
The membrane was estimated to be in the range of from 0.2 to 0.6 micron in thickness.
A balsa wood frame forming a square opening 16 cm on an edge was placed upon the membrane to protect an area, and the membrane outside the frame was then col-lapsed by cru~hing it against the frame. The micro-cellular fiIm support was coa~ed with this membrane by ~immersing the filn support in the ~ater contained in the tray and then withd~awin~ it throug~ the membrane with the microcells on the upper 6urface of the film support. The '6:S'~

combined membrane and microcellular film support, with most microcells now containing w~ter~ was then dried, 80 that no water remained ~ a liquid within the microcells.
In order to increase the light absorbing capa-bility of the membrane, the outer membrane surface waspassed rapidly through the incandescent portion of a candle flame. Undel microscopic examination, carbon could be seen on the outer surface of the membrane.
To open a first set of microcells, the micro-cellular film support with the membrane present providinga lightly carbon-coated outer surface was subjected to irradiation with a ~47 nanometer laser beam in a pattern of laterally spaced lines. The beam power was in the 12 to 28 milliwatts per square centimeter range, and the beam cross-section was about 23 microns. Where the laser beam struck the membrane, the cells were uncovered in a sin~le or double line, depending upon the power and placement of the beam.
To form materials for selectively filliog micro-cells, three subtractive primary filter dye compositionswere prepared as described belowj identified as Yellow Dye Dispersion A, Magenta Dye Dispersion B, and Cyan Dye Dispersion C. The filter dye was in each instaoce chosen to be immobile, thereby avoiding transfer from the micro-cells once introduced.
To form the compositions actually used to filleach o tbree separate sets of microcells, two of the subtractive primary dye dispersions identified above were blended to form an additive primary filter material. An initially mobile and colorless subtractive dye-forming coupler was also blended with the two subtractive primary filter dyes. (The mobile couplers were, of course, immobile in the microcells, since mobility refers only to mobility upon contact with a pbotographic processing solu-tion.) s~

Yellow Dye Dispersion A
A conventional aqueous-oil dispersion was pre-pared by homogenizing 40 grams yellow dye 3{ 3-[~-(2,4-di-t-pentylphenoxy)acetamido]benzamido}-4-(4-meth-oxyphenylazo)-1-(2,4,6-trichlorophenyl)-2-pyrazolin-5-one, 120 grams auxiliary solvent 2-(2~butoxyethoxy)ethyl acetate and 27.2 grams gelatin diluted to 454 grams with water. Following homogenization, the dispersion was chill-set and noodle-washed to remove the auxiliary 10 solvent.
Magenta Dye Dispersion B
A conventional aqueous-oil dispersion was pre-pared by homogenizing 40 grams magenta dye 3-{3-[~-(2,4-di-t-pentylphenoxy)acetamido]benzamido}-N-{4-[N-15 ethyl-N-~2-hydroxyethyl)amino]-2-tolylimino}-1-(2,4,6-trichlorophenyl)-2-pyrazolin-5-one, 80 grams permanent solvent 1,4-cyclohexylenedimethylbis(2-ethylhexanoate), 80 grams auxiliary solvent cyclohexanone, and 60 grams gelatin diluted to 1000 grams with water. Following 20 homogenization, the dispersion was chill-set and noodle washed to remove the auxiliary solvent.
Cyan Dye Dispersion C
A conventional aqueous-oil dispersion was pre-pared by homogenizing 40 grams 2-[4-(2,4-di-t-pentyl-25 phenoxy)butylcarbamoyl]-N-{-4-[N-ethyl-N-(2-hydroxy-ethyl)amino]-2-tolyl}-1,4-naphthoquinooe 4-monoimine, 80 grams permanent solvent 1,4-cyclohexylenedimethyl bis-(2-ethylhexanoate), 80 grams auxiliary solvent cyclo-hexanone, and 60 grams gelatin diluted to 1000 grams with 30 water. Following homogenization, the dispersion was chill-set and noodle-washed to remove the auxiliary solvent.
Dry Red Microsphe_e Dispersion Beads First, 30 grams of yellow dye dispersion A and 30 35 grams of ~agenta dye dispersion B were melted together and dilutPd to 750 ml with water. Next, 3.0 grams cyan dye-forming coupler, l-hydroxy-N-[2-(2-acetamido)phenethyl]-2-naphthamide, were dissolved in a minimum amount of ethyl ., 1~6~;t'i~

alcohol and 5 percent s~dium hydroxide and added to the solution of dispersions.
The resultant mixture was passed through a DeVilbiss~ tModel 65) ultrasonic nebulizer and into a heat jacketed drying column where the water was evapo-rated. The resultant dry red microsphere dispersion beads containing a cyan dye-forming coupler were collected and examined microscopically. They were approximately three microns and smaller in size.
Dry Green Microsphere Dispersion ~eads Yellow dye dispersion A, 20 grams, and cyan dispersion C, 40 grams, were melted together and diluted to 750 ml with water. Magenta dye-forming coupler, 3-(4-nitroanilino)-l-(2,4,6-trichlorophenyl)-2-pyrazolin-5-one, 3.0 grams, dissolved in a minimum amount of ethylalcohol and 5 percent sodium hydroxide were added to the solution of dispersions. Following treatment in ~he nebuli~er and drying column, dry green microsphere disper-sion beads containing a yellow dye-forming coupler were obtained.
Dry_Blue Microsphere Dispersion Beads Magenta dye dispersion B, 30 grams, and cyan dye dispersion C, 30 grams, were melted together and diluted ~ to 750 ml with water. Yellow dye-forming coupler, ~-(4-carboxyphenoxy)-~-pivaloyl-2,4-dichloroacetanilide, 3.0 grams, dissolved in a minimum amount of ethyl alcohol and

5 percent sodium hydroxide were added to the solution of dispersions. Following treatment in the nebulizer and drying column, dry blue microsphere dispersion beads containing a yellow dye-forming coupler were obtained.
The microcellular film support with the membrane tbereon destroyed in laterally spaced lines to open a first interlaid set of microcells was covered with the green micros~here di~persio~ beads. The dispersion beads were introd~ced into the opened microcells with a flexible rubber blade with excess beads being removed by brushing.
Microscopic examination showed that microcells not struck by the laser beam still retained a membrane cover.

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:

The microcellular film support with the membrane thereon ~as again scanned with the laser microheam, but at an angle eo the first li~ear scan. As before, the laser microbeam removed mem~rane in areas contacted, leaving a second, interlaid set of microcells uncovered. The newly uncovered microcells were filed with ~lue microsphere dispersion beads by the same procedure described a~ove for filling with the green microsphere dispersion beads.
Thereafter, the remnants of the membrane were removed with an adhesive tape, opening the third interlaid set of microcells. The newly opened microcells were filled with the red microsphere dispersion beads. Excess fill material was then lifted from the microcellular face of the film support using adhesive tape.
The resulting three color microcellular filter array was placed in a high relative humidity environment overnight. The microcell contents ~ecame less scattering and appeared to be partially fused.
Example 2 The procedure of Example 1 was repeated, except that the balsa wood frame was immersed in the water beneath the membrane and lifted upwardly to raise the membrane from the surface of the water. Thereafter the microcellular support element was gently laid on the membrane so that the mem~rane closed the microcells. The support element with the membrane in place was flexed so that the first major surface bearing ~he microcells was convex. FiDal setting of the membrane occurred with the support in this configuration.
Example 3 The procedure of Example 1 was repeated, except that the composition of the casting solution was varied.
The casting solution employed to form the membrane con-sisted of 8.5 grams of cellulose acetate and 42.0 grams of solvent. The solvent consisted of 80 ml of dichloro-methane ~nd 20 ml of methanol contsining 0.6 g of Genacryl Blue dye to enhance the radiation adsorption of the mem-brane. No carbon was placed on the surface of the mem-brane.
Example 4 The pro~edure of Exam~le 1 was Iepeated, except that the composition of the casting solution was modified to include 1 g of Sudan Black B, wet with 10 drops of dichloromethane per 12 g of casting solution. No carbon was placed on thP surface of the membrane.
In both Examples 3 and 4, the membranes adsorbed sufficient radiant energy from the laser to permit their local destruction to open selected microcells.
The invention bas been described in detail with particular reference to preferred embodiments there-of, but it will be understood that variations and modifi-cations can be effected within the spirit and scope of theinvention.

Claims (26)

WHAT IS CLAIMED IS

1. In a process comprising forming in a support having first and second major surfaces a planar array of microcells of from 1 to 200 microns in width opening toward the first major surface and selectively altering the contents of a first set of the microcells in relation to a second, interlaid set of the microcells, the improvement comprising selectively altering the contents of the microcells by positioning to overlie the first major surface, means for closing both the first and second sets of microcells and selectively removing the closing means from the first set of microcells to permit selec-tively altering the contents of the first set of microcells without concurrently altering the contents of the second set of microcells.

2. The improved process according to claim 1, wherein the microcells are from 4 to 100 microns in width.

3. The improved process according to claim 1, wherein the means for closing comprises a membrane.

4. The improved process according to claim 3, wherein the membrane is comprised of an organic film-forming polymer.

5. The improved process according to claim 4, wherein adjacent microcells are separated by lateral walls formed by the support and the membrane is of a thickness in the range of from 5 to 50 percent the thickness of the lateral walls.

6. The improved process according to claim 5, wherein the membrane is from 0.2 to l.0 micron in thickness.

7. The improved process according to claim 5, wherein a laser is employed to selectively remove the membrane from the first set of microcells.

8. The improved process according to claim 7, wherein a means is provided in contact with the membrane to increase its absorption of radiation.

9. The improved process according to claim 1, comprising altering the contents of the first set of microcells by selectively introducing a radiation-sensitive material, dye, or dye precursor therein.

10. The improved process according to claim 9, comprising removing the closing means from the first major surface after selective introduction into the first set of microcells and positioning a second closing means over the first major surface to close both the first and second sets of microcells.

11. The improved process according to claim 10, comprising selectively removing the closing means from the second set of microcells without concurrently altering the contents of the first set of microcells.

12. The improved process according to claim 1, wherein the contents the first and second sets of microcells are comprised of a radiation-sen-sitive material, pigment, dye, or dye precursor comprising altering the contents of the first set of microcells by selectively removing the radiation-sensitive material, pigment, dye, or dye precursor therefrom while retaining the radiation-sensitive material, dye, or dye precursor in the second set of microcells.

13. The improved process according to claim 12, comprising further altering the contents of the first set of microcells by selectively introducing a second radiation-sensitive material, dye, or dye precursor therein differing from the radiation-sensitive material, dye, or dye precursor in the second set of microcells.

14. In a process of forming a multicolor filter comprising forming in a support having first and second major surfaces a planar array of microcells of from 4 to 100 microns in width opening toward the first major surface and introducing into an interlaid pattern of first, second, and third sets of the microcells blue, green, and red filters, respectively, the improvement comprising positioning an organic film-forming membrane to close the microcells opening toward the first major surface, and laser addressing the membrane to open the first set of microcells, thereby permitting the contents of the first set of microcells to be altered without altering the contents of the second and third sets of microcells.

15. The improved process according to claim 14, comprising employing means for facilitat-ing membrane absorption of laser radiation.

16. The improved process according to claim 14, comprising aligning a radiation-sensitive imaging means adjacent the microcells containing the blue, green, and red filters.

17. The improved process according to claim 16, wherein the radiation-sensitive means is silver halide.

18. The improved process according to claim 17, comprising incorporating yellow, magenta, and cyan dyes or dye-forming precursors capable of shifting between mobility and immobility as a function of silver halide development into the microcells containing the blue, green, and red filters, respectively.

19. A process comprising casting an organic polymeric membrane of from 0.2 to 1.0 micron in thickness on the surface of a liquid, positioning the organic polymeric membrane on a support to overlie and close an array of microcells of from 4 to 100 microns in width separated by lateral walls and opening toward one major surface of the support, the thickness of the lateral walls being at least twice the thickness of the membrane, laser addressing the membrane in a pattern corresponding to a first set of microcells of the array, sufficient energy being transferred to the membrane in addressed areas to thermally destroy the membrane thereby opening the first set of microcells while leaving the membrane intact overlying and closing second and third interlaid sets of micro-cells of the array, introducing into the first set of microcells a first composition , laser addressing the membrane in a pattern including the second set of microcells and excluding the third set of microcells of the array, sufficient energy being transferred from the laser to the membrane in addressed areas to thermally destroy the membrane thereby opening the second set of micro-cells while leaving the membrane intact overlying and closing the third interlaid set of microcells of the array, introducing a second composition into the second set of microcells, removing the membrane from the third set of microcells, and introducing into the third set of microcells a third composition, said first, second, and third compositions each being selected from a differing one of the following:
(a) a composition comprised of at least one of red responsive silver halide, a red filter material, and a cyan dye or dye precursor capable of shifting in mobility in response to silver halide development, (b) a composition comprised of at least one of blue responsive silver halide, a blue filter material, and a yellow dye or dye precursor capable of shifting in mobility in response to silver halide development, and (c) a composition comprised of at least one of green responsive silver halide, a green filter material, and a magenta dye or dye precursor capable of shifting in mobility in response to silver halide development

20. The combination comprising support means having first and second major surfaces and forming a planar array of microcells of from l to 200 microns in width opening toward said first major surface and a destructable membrane overlying said first major surface, to close a plurality of the micro-cells of said planar array.

21. The combination according to claim 20, in which the microcells contain a thermally insula-tive material.

22. The combination according to claim 20, in which the microcells contain air.

23. The combination according to claim 20, in which at least a first set of the microcells contain a dye or dye precursor.

24. The combination according to claim 23 in which a second, interlaid set of the microcells contain a different dye or dye precursor.

25. The combination according to claim 23, in which the first set of microcells contain radia-tion-sensitive imaging means.

26. The combination according to claim 25, in which the first set of microcells contain radia-tion-sensitive silver halide.