DE2438063A1 - IMAGE RECORDING ELEMENT - Google Patents

Description

25 527

XEROX Corporation, Rochester N-Y. / UNITED STATES

Imaging element

The present invention relates

refer to an imaging element corresponding to the The preamble of claim 1. "

They are already different

Image recording elements known in which an image recording is carried out by photo voltages or currents corresponding to the image distribution voltage or current sensitive recording medium are fed. Such image recording elements are, for example, Ruticon-E learning, xerographic ones Copy devices, prefabricated elements, phototitus elements and liquid crystal elements. Allowed for these elements the radiation incident on a photoconductor, that

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Charge carriers are moved within an external electric field. These charge carriers act on a tension or current-sensitive element, which in turn results in a light modulation.

With Ruticon elements (see

for example IEEE Transactions On Electron Devises, September 1972) there is the voltage-sensitive light-modulating Recording medium made of a deformable elastomer layer / while the photoconductive material as may be formed as a separate layer or embedded within the elastomer layer. This results in various Ways to get to the elastomer layer To generate an electric field by, for example, a thin metallic layer is provided, which above the elastomer layer serves as an electrode. Such embodiments are referred to as gamma-ruticon elements.

With phototitus elements (see

For example, Applied Physics Letters, Vol. 21, No. 3 of August 1, 1972) a sandwich construction is provided in which a KD ₂ Pö - Kristari is provided in the form of a voltage-sensitive light-modulating layer, which is arranged in the area of a photoconductor layer . The KD ₂ PO ₄ crystal acts on the voltage distribution of the photoconductor layer, which is determined by incidence of light, by changing the polarization of the transmitted light by using the so-called electro-optical effect or Pockei effect.

With prefabricated elements (see

Electronics dated February 1, 1971 and Applied Physics Letters Vol. 24, No. 4 of February 15, 1972) is considered a tension

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The sensitive light-modulating element is a PLZT ceramic material, ie a lead zirconate titanate doped with lanthanum. Similar to the KD-PO.-Crystal! In the case of phototitus elements, the PLZT ceramic material responds to a changed electrical field, which is generated with the help of the photoconductor layer by changing the polarization of the transmitted light. In contrast to KD ₂ PQ ^ -KrIstalleji · - · the effect created in the PLZT-Kexamik material does not disappear when the electric field is removed. Because of their similarities, phototitus elements and prefabricated elements are referred to below as electro-optical elements.

There are also various

Image recording elements are known in which liquid crystalline material is used as the recording medium (see, for example, Applied Physics Letters _f Vol. 19, No. 7 of October 1, 1971). In the case of these elements, the light-modulating liquid crystal layer can be either voltage-sensitive or current-sensitive. Such elements can contain, for example, nematic liquid-crystalline materials which, with a view to achieving a recording medium, have appropriate light modulation properties as soon as they are operated below a certain threshold voltage. Various nematic mixtures. Materials also have dynamic light scattering as soon as they are exposed to an electrical current. =

Αλι | the prince of the xerographic

Reproduction-working copiers also fall into the group of buyers. ^ - pild ^: §uf zelchnipitgse In xerographic copiers, due to: of,: changes to a toner material on certain parts. Provision of a photoconductive element gum Haffcen;., In contrast to other types., Of image recording elements

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one in xerographic copiers a separation of the photoconductor and the voltage-sensitive recording medium, i.e., the toner, these two elements generally being attached to other elements.

The entire group of image recording elements for the recording of optical Images with the help of an image-wise distribution of photo-generated voltages or currents to voltage or current-sensitive ones Recording media can be used for explanation with the help of an inFig. 1 shown image recording element explained. This generalized imaging element consists of an opaque or transparent conductive Substrate 2, a photoconductive insulating layer 4, a voltage or current sensitive light modulation layer 6 and a surface charging device in the form of a conductive layer 8, which with one pole of a Voltage source 1o is connected. However, it should be understood that the conductive layer 8 can be eliminated in those cases in which a corona charger (see e.g. U.S. Patents 2,836,725 and 2,777,957) are used is used to generate charge carriers on dex surface of the light modulating Apply layer 6. It should also be understood that layers 2 and 8 can be eliminated by using double-sided corona chargers, around the surfaces of the two layers 4 and 6 with charge carriers to apply. In this latter case, there will be two on either side of the dildographic element oppositely charged charging devices are used, which are moved more or less simultaneously. In Cases in which the substrate is used as an image recording element. is used, it need not be conductive if a double-sided corona charger is used.

3AD

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Electo-optical imaging elements corresponding to Fig. 1 have an increasing importance, because with the same very satisfactory results are achievable. The Ruticon elements invented by Sheridon are of particular interest because of their excellent properties and because they are related can be used with a wide variety of applications. It is found, however, that this type of imaging element can still be further improved, so that they are even more important for a wide variety of applications gain.

In the case of the one shown in FIG

The general form of image recording elements is the voltage or current sensitive light modulation layer generally still sensitive to charge carriers, which after the activation radiation for the production an image in the photoconductive layer. Accordingly, the storage time is generally limited because the charges generated within the photoconductor tend to affect the recorded Picture either to lccwhen odci to change the contrast (It should be noted in this connection that for some liquid crystal elements and prefabricated elements, the stored Image is not sensitive to charge carriers generated within the photoconductor. This attribute is reinforced with certain image recording elements in which the image reconstruction or The light used for reading out is not optically separated from the imaging radiation. There one Activation radiation is generally used for readout; there is a tendency for the image to be erased more quickly will. Even with Gamma Ruticon learners, which have an optical isolation between the imagewise activation radiation and the readout exposure, in that on

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a metal layer is provided on one side of the elastomer layer there is a desire to reduce the level of light transmission of this layer in some cases, although it is not practical to have a relatively dense layer of metal to apply on the elastomer.

With some image recording

elements, a certain number of charge carriers are generated spontaneously within the photoconductor or less Speed injected through electrodes. There is a desire that the voltage or current sensitive Light modulation layer is electrically separated from these charge carriers after an image has been formed is. In the case of gamma roticon elements, it results, for example, that the primary limit on image storage time for certain photoconductors is due to dark decay of the photoconductor is determined.

For imaging elements

of the general type according to FIG. 1, the optimal electric field strength for controlling the voltage or current sensitive light modulation layer is not optimal for the photoconductor. However, since these elements are generally subjected to the same voltage source. it is generally necessary to operate the imaging element at a compromise voltage which is not optimal for either element.

It is therefore the goal of

present invention to provide an imaging member in which the individual layers can be electrically separated from one another.

This becomes according to the invention

achieved by the features listed in the characterizing part of claim 1 are provided.

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In the context of the present

In accordance with the invention, at least one electrical grid is provided within a multilayer image recording element, which has a voltage or current sensitive light modulation layer and a charge carrier generating layer Layer possesses, with the help of the electrical grid an electrical field separation between these two Layers can be caused. The electric grid is a continuous or piecemeal one continuous three-dimensional structure, which has relatively large open areas on the order of 95% and above, consequently charge carriers can flow through these areas while on the on the other hand, the electrical grid has sufficient electrical conductivity, so that an electrical Field separation between adjacent layers is possible. The electrical grid can be an electrical one be continuous grid of conductive material, in which all points of the surface of the grid on the same electrical potential. The electrical grid can, however, consist of a network of electrically isolated islands of There are conductive material, as a result of which a plurality of lattice structures occur, which are electrically from each other are isolated.

When using such a

Lattice between adjacent layers of one multilayer electro-optic imaging elements enable the open areas of the electrical grid the flow of charge carriers between the layers as soon as the voltage values and other states - for example imagewise photogeneration of carriers - is inexpensive, while there is a relatively low probability is that a loss of charge carriers due to contact with the electrical surfaces of the lattice structure

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takes place. In addition, the electrical grid can be used a layer of a dielectric material, a semiconductor material, or a photoconductive material applied if so for the particular imaging configuration is desirable. In many applications, the electrical grid is near one Buffer layer or arranged between two buffer layers, as will be discussed in the following.

The electrical grid in conjunction with one or two buffer layers allows one electrical field separation of the photovoltage or current-sensitive element from the electro-optical picture element, however, allows the passage of both electrical charge carriers and light. In this context it should be emphasized that the electrical grid acts similar to the grid of a vacuum triode. In contrast to a vacuum tube, in which the grid for generating a temporal modulation of an electron beam for the control of a one-dimensional Is used to transmit information, the electrical used in the context of the present invention is used Grid for controlling two-dimensional information transmission by spatial modulation of the charge carriers. The spatial modulation of the charge carriers is however not necessarily carried out to produce temporal information, but rather serves to allow charge carriers to pass through, which due to their zv / one-dimensional spatial Own distribution of information content.

The invention is now based on

of exemplary embodiments explained and described in more detail with reference to the accompanying drawing j.-k .. Show it:

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BATH ORIGINAL

Fig. 1

a schematic sectional view of a known image recording element, which is a voltage or current sensitive Has light modulation layer,

Fig. 2

a schematic sectional view of an embodiment of the Image recording element according to the invention, which with is provided with an electrical grid,

Fig. 3

a graphical representation of the electric field distribution in an image transmission element with an electric grid according to the invention,

Fig. 4

a photomicrograph of an electrical grid constructed in accordance with the invention,

Figures 5, 6 and 7

schematic sectional views of image recording elements according to the invention, in which a deformable elastomer layer serves as a recording medium,

Fig. 8

Fig. 3 is a schematic sectional view of an imaging member according to the invention, in which two separate electrical grids are provided,

Fig. 9

Fig. 3 is a schematic sectional view of an imaging member according to the invention, in which an insulating grid is additionally provided in the area of the electrical grid is,

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Figure 10 is a schematic sectional view of an imaging member according to the invention, in which in the area of the electrical grid additionally a photoconductive one Grid is provided,

11 is a schematic isometric view of a further embodiment of the invention in which the imaging element is matrix addressed,

Figure 12 is a schematic sectional view of the imaging member of Fig. 11,

Figure 13 is a schematic sectional view of an imaging member according to the invention, which with a piezo-sensitive Layer is provided,

14 shows a schematic sectional view of an embodiment a xerographic element according to the invention, and

15 shows a schematic sectional view of a further embodiment a xerographic element according to the invention.

Figure 2 shows a typical multilayer electro-optic imaging element according to the invention. According to the figure, there is this imaging element 12 from an optionally transparent or opaque conductive substrate 14, a photoconductive one Insulating layer 16, buffer layers 13 and 2o, an electrical grid 22 and a voltage or current sensitive

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Lichen light modulation layer 24. In addition, two voltage sources "V _7. and V_" are provided, which emit either direct voltages, alternating voltages or combinations thereof. Although the electrical grid 22 is shown in the figure between the two buffer layers 18 and 20, it should be understood that one or both of these buffer layers can be removed in cases in which they are not needed. In the embodiment shown in Fig. 2, the electrical grid 22 is used to separate the photoconductive insulating layer and the voltage or current sensitive light modulation layer 24 from one another With this type of electrical separation, it appears possible to pass activation light used for reading through the photoconductive insulating layer 16 after an image has been generated within the voltage or current-sensitive light modulation layer 24. In this way, the image information can be read out en. Of course, the reading can also be done by light reflection. Finally, it is also possible to apply an electric field to the photoconductor for a certain period of time during the image recording, whereby the effect of an electronic shutter or a diaphragm is brought about. In this connection it should be mentioned that the conductive substrate 14 can be eliminated if a corona charging device is used in order to apply charge carriers to the surface of the insulating layer 16. The surface charging device (not shown) and the substrate 14 can also be eliminated if double-sided corona charging is used to apply charge carriers to the surface of the two layers 14 and 24.

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The functioning of the in Fig. 2

The image recording element 12 shown here is as follows: A voltage of the voltage source V_ is applied between the electrical grid 22 and the conductive substrate 14. If the photoconductive layer 16 is then exposed to imagewise irradiation, which is indicated in FIG. 2 by the arrows, photo-generated charge carriers are formed which are attracted by the electric grid 22 by the electric field. _{Furthermore, the voltage of the voltage source V n is} applied between the electrical grid 22 and the voltage- or current-sensitive light modulation layer 24. As soon as the photo-generated charge carriers approach the area of the electric grid 22 , some of these charge carriers come under the influence of the voltage source V , which penetrates a short distance into the buffer layer 2o through the openings in the electric grid 22. The electric field caused by the voltage source V 1 pulls these charge carriers through the electric grid 22 into the region of the buffer layer 18, so that they do not precipitate on the electric grid 22.

If long-term storage of the image is desired, after the transfer of the charge image to the buffer layer 18, the voltage of the voltage source V _{β is} either switched off or the polarity reversed so that no further charge carriers can be fed to the buffer layer 18. It should be understood, however, that this step is not necessary for the formation of the image. The charge carriers present in the buffer layer 18 then modulate the _{external voltage caused by the voltage source V A} or result in a current, as a result of which an image is formed within the voltage or current-sensitive light modulation layer. Charge carriers generated within the photoconductive layer 16, which either by activation of the used for reading, by the

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Layer of light let through or spontaneously caused as a dark current can then not enter the buffer layer 18 penetrate. In the case where the light modulation layer 2 4 is substantially voltage modulated, The image is generally formed by collecting the photo-generated supports at the interface between the stress-sensitive light modulating layer 24 "and the buffer layer 13 saved. The storage phenomenon can be explained in terms of a very thin collecting layer, which occurs in the area of mutual contact. This collecting layer prevents sideways migration of the stored charge carriers over a certain period of time. . .

In general, one of the

electric fields stronger than the other, the stronger field being arranged with respect to the weaker field in the direction in which there is a desire to induce movement of the charge carriers. It should be understood, however, that this state is generally only maintained during the period of time during which the image exposure is taken. As soon as the exposure has ended and there is a desire to fix the image formed in the voltage or current-sensitive light modulation layer, the voltage of the voltage source M is reduced to almost zero or the polarity reversed. ■

The deletion of the image can ■

be done by removing the field on the voltage or current sensitive light modulation layer or by changing the polarity of the field on the light modulation layer is changed. According to an advantageous Embodiment of the invention, the photoconductive layer is simultaneously with the removal or IM-

BATH ORIGINAL

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polarization of the field of a uniform activation radiation exposed, causing faster erasure.

The conductive substrate 14

can consist of any conductive material and optionally transparent or opaque. The substrate 14 may consist of a single layer of a conductive Material or have a transparent conductive layer, which on a suitable substrate, for example gas or plastic material is applied. Transparent conductive layers are usually conductive Coatings of conductors such as indium oxide, tin oxide, thin layers of tin, aluminum, or chrome another suitable conductor. These generally transparent conductive layers are generally used evaporated onto a more insulating transparent substrate. An example of a commercially available element is NESA glass, a tin oxide coated glass which manufactured by Pttsburgh Plate Glass Company.

Any photoconductive insulating material can be used to form the layer 16. Such Photoconductive materials are, for example, selenium, poly-N-vinylcarbozole (PVK), with sensitizers such as brilliant Green dye and 2.4.7-trinitro-9-fluorenone (TNF), doped poly-N-vinyl-carbzole, cadmium sulfide, cadmium selinide, Zinc oxide, sulfur, anthracene and tellurium. The photoconductive layer 16 can also be very fine-grained photoconductive Insulating material within a binder with a high electrical resistance accordingly U.S. Patent 3,121,006, Inorganic Photoconductive Insulating Materials according to US-PS 3.l21.oo7 or organic photoconductors such as Contain phthalocyanine in conjunction with a binder. in the generally one can use for the production of the layer 16

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any photoconductive insulating material or equivalent Composition can be used.

The thickness of the photoconductive

Layer 16 is in the range between o, 1 and 2oo, u and about that. In each case, the thickness of the layer depends, among other things, very much on the spatial frequency of the Information and sensitivity to image radiation away. The photoconductive layer 16 can be deposited on a substrate 14 in various ways - for example through Vacuum evaporation, solution immersion, etc. - created will.

As mentioned earlier, this is

electrical grids 22 either electrically continuous or piecewise continuously and has a three-dimensional Structure provided with open areas that make up 95% and above of the total area. The electrical grid 22 can be an electrical continuous structure of a conductive material or consist of a plurality of electrically continuous structures which are isolated from one another, which is possible, for example, by providing separate grid areas. Preferably the electrical grid is 22 coated with an insulating semiconducting or photoconductive insulating layer, as in the following will be described. In these cases, the semiconducting or photoconductive insulating material is preferably in conformity applied to the same with the electrical grid. The basic requirement for the electrical grid is that it has an electrical conductivity which is sufficiently high to maintain a desired voltage distribution. The resistance value of the electrical grid in the area of the surface is · in generally in the range from 10 to 10 ohms per cm and

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is preferably about 100 ohms per cn. The resistance value should be low enough to be sufficient To supply charge carriers, so that within the image recording element the desired field distribution is maintained. However, this requirement can be very easy achieved with the help of grids, which are made of a sufficiently thick layer of a material. An electrical grid 22 generally has a thickness between Io and 1 mm, the most convenient value being

ο
is in the range of about 200 A. As already mentioned, the electrical grid 22 should have relatively large open areas so that a satisfactorily high ratio between the open areas and the electrically conductive areas is achieved. The ratio of the open areas to the electrically conductive surface areas can be between 1% and almost 100%. At the same time, the electrical grid 22 should be designed in such a way that the electrical field from one side of the grid cannot penetrate too strongly into the area of the other side of the grid. This means that the individual grid openings should be relatively small, while at the same time the electrically conductive surface is also made small. Dias again requires that the ideal electrical grid 22 should generally be designed in a manner similar to a fine-pored wire grid made from eight ilurmon wires. The Po:> egg dimension should be in the range between 1o Λ and 1oo, u, a typical value being around 2 .u.

The geometric design of the

electrical grid 22 is, inter alia, very wide by the arrangement within the image recording element and the Properties of voltage or stress sensitive light modulationsschich'- in connection with the respective application confidently. If the electric grid 22

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at a sufficient distance from a voltage-sensitive one Light modulation layer is arranged, accordingly a uniform stress distribution in the latter gives rise to the geometric configuration of the grid no operational problems, so any configuration can be used. Those of different Electric fields resulting from charge designs are, for example, in Applied Optics, Vol. 3, March 1964, p. 385, discussed. In the vicinity of these grid designs, the electric field becomes very strong due to the geometry of the grid influenced. At larger distances, however, the field corresponds largely a uniform charge distribution.

The electrical grid 22 can

with respect to the voltage or current sensitive light modulation layer be arranged so that a non-uniform stress distribution occurs within it. This situation can be dealt with in two different ways. On the one hand, this may not be uniform Stress distribution can be used as a carrier for the information to be read from the optical element, like this is the case with a kuticon element provided with a grid, in which the grid acts as a support. On the other hand, however, it can be even more desirable to be perfect or at least to a large extent to keep the influence of the electrical grid on the optical information small. In In cases where this is desired, the electrical grid 22 should be designed so that there is no spatial Has frequency components which are within the spatial frequency band of the voltage or current sensitive light modulation layer lie. Accordingly, the fact that in most, if not In all cases, the voltage or current sensitive light modulation layer has a maximum sensitivity to it the tension vertexes, which within the

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spatial frequency bandwidth a. If the electrical Grating spatial frequency components above a certain level possesses spatial cut-off frequency, then represents the voltage- or current-sensitive light modulation layer the same not validly established. Accordingly, in this case, the electric grid gives a uniform electric field for the light modulation layer. This influence becomes natural reinforced by this / by placing the electrical grid at the greatest possible distance from the voltage. or current-sensitive light modulation layer is arranged.

In general, it appears advantageous if the electrical grid 22 in comparison to FIG Thickness of the adjacent layers is relatively thin. This means that there is minimal mechanical disruption to the tension or current-sensitive layer with regard to a disturbance of the optical signal. In some embodiments of the imaging element of the invention it seems desirable to have an anti-injection layer to be arranged on both sides of the electrical grid / that the grid is prevented from at very strong field conditions to deliver charge carriers. An anti-injection layer is in all of one layer, which allows the injection of charge carriers via the swipe surface between two adjacent layers. The anti-injection layer can, for example consist of an electrically insulating material. However, such an anti-injection layer may also be Be charge carrier trapping layer. After all, a Anti-injection layer can also be formed by a Fermin level adjustment comes about, accordingly Charge carriers cannot migrate from one layer to the next. However, it can also be another Mechanism can be used. The anti-injection layer generally has a thickness in the range between

ORIGINAL

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■ ο. ο. . ·

1ο A and Ι00,000 A and is preferably in the range of

500 A. The total resistance is also in general more than 10 ohm-cm. Suitable materials for the Examples of production of the anti-injection layers are nylon, polystyrene or polytetrafluoroethylene. The vote of a certain material depends very much on the layers next to it. ·

How the electric

Grating in an imaging element according to the invention seems easier to understand in connection with FIG. It should be understood, however, that the present invention should not be limited by any theoretical mechanism. The one to understand how it works However, the mechanism shown is only intended to help those skilled in the art to understand the essence of the present invention. Fig. Figure 11 shows the electrical field configuration in an imaging element provided with an electrical grid is provided according to the invention; the individual curves within this figure have been obtained through experimental measurement of the electric field on a two-dimensional model of the lattice structure using standard electric field recorders were used. However, the resulting results can be applied directly to three-dimensional structures as they are with imaging elements occur according to the invention. According to FIG. 3, three electrodes 26, 28, 3o are provided, which are connected to voltage sources 32, 34, the example ™ wise consist of a 1 1/2 volt and 6 volt battery. The electrode 28 is electrically continuous and stationary in electrical communication with segments 36a, 36b and 36c. Be it. mentioned that the electric field between the Electrodes 2 8 and 3o is much stronger than the electric field between electrodes 28 and 26. The thin out-

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Drawn lines represent lines of the same electrical power The result is that these lines push through in the area of the openings in the electrical grid. The thin dashed lines show the electric field lines, along which essentially the charge carriers flow from the electrode 26 in the direction of the electrodes 28 and 3o if the current densities are low be accepted.

It turns out that on both

Sides of the electrode 2 8 and the electric grid 36 the electric fields in the vicinity of the electrodes 26 and 3o are the same. As a result, the electric field in the vicinity of the electrode 26 becomes perfect by the influence of the electric grid is shielded from the electric field between the electrodes 28 and 3o. Closer to the Electrode 28, however, has a different electric field configuration on either side of the grid. Nearby of the electrode 28, the electrical field configuration is very strongly influenced by the field between the electrodes 28 and 3o. In the field conditions shown, the charge carriers emitted by the electrode 2 € have a very high low probability of trapping compared to dsm electric grids when approaching them. Much of the Charge carrier thus passes through the open areas of the electrical grid, so that this part is in the direction of the Electrode 3o can migrate. It should be noted that the electric field lines are each perpendicular to the equipotential lines get lost.

It thus follows that the

electrical grid an electrical field separation between the layers of the imaging element - for example of a solid metallic conductor - yields while

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at the same time a free passage of the charge carriers while maintaining the correct electrical field conditions is made possible. It should also be noted that the electrical grid also allows the free passage of light, There are relatively large open areas.

The electrical grid can be manufactured using a wide variety of methods. A relatively straightforward method is to use photoresist materials. The surface, on which the electrical grid is applied is initially coated with a layer of a suitable photoresist. standsraaterials coated. A design of an electrical The grid will then appear on the surface of the photoresist material - Applied, for example, by focusing an optical image or an electron beam image, or by exposing the layer through a mask placed on the grating. The photoresist layer is then developed, with corresponding areas of the photo material being removed, which leads to exposure of the underlying layer. In this way a mask is formed to be desired in Way to apply the electrical grid material to the carrier layer. A layer of the electrical grid material - generally metal - is then applied within a vacuum. The remaining photoresist material is then removed chemically, leaving the electrical grid on the support surface will. The following layer can then be applied to the element. On the surface on which the electrical grid is to be produced, a metal layer can also be applied, whereupon a another layer of a photosensitive material is applied. The photosensitive layer is then exposed and developed, whereupon the exposed areas of the metal

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The layer is chemically removed, eventually leaving the remaining photovidarstanasra material chemically removed. It should be understood that in some Cases the photoresist procedure does not connect can be used with surfaces on which an electrical grid is to be applied. For example can be used in conjunction with the photoconductive materials solvents used the poly-N-vinyl carbzene layers attack.

Another experimental

A tested method for the production of an electrical grid is to coat the surface in question with a suspension of particles within a solvent before the solvent is evaporated, thus causing the particles to adhere to the surface wherever they are can be used as ilask particles for making the grid. For example, it has been found experimentally that if a glass plate with a suspension of styrene, each having a diameter of approximately 1 Chemical Co.) there is a very strong tendency to form a 1 particle thick layer with a very high packing density, which has an arbitrary orientation Chromium - applied to a plate coated in this way in a vacuum and then the latex beads are blown away, the shadows of the beads then formed an excellent, laterally conductive grid, which has open areas greater than 90 % .

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The optical performance spectrum

such a grating is concentrated very strongly around a spatial frequency which is very far · above the most effective spatial frequency sensitivity of many voltage and current sensitive light modulation layers is. This method gives a better influence on the shape of the grid openings, their sizes and distribution, than the use of photoresist materials.

Similar processes can also be used for the manufacture of the photoconductive grid or the insulating grille can be used. A 'photoconductive grid can for example be produced thereby be by placing a photoconductive insulating material such as selenium in a vacuum directly on the previously made electrical Grid is applied. Other photoconductive materials like cadmium sulfide, cadmium selenide, etc. can also applied in accordance with this process in a vacuum. However, photoconductive ones can also be used Materials used which are normally applied by immersion processes. Certain Areas of these photoconductive layers can then be removed with the aid of a suitable solvent or with the aid of Solvent etching processes are removed. An insulating grid can be created by applying layers of materials such as prylene (Union Carbide Co.), aluminum oxide or silicon monoxide can be produced in a vacuum. Such insulating grids can, however, also by sputtering thin Layers of different dielectric materials are produced.

Another method of making electrical grids is by making island-forming Ground materials applied in a vacuum. This process requires the application of a material in a vacuum

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onto a substrate, which material has a tendency to form inaein. Then an electrode * material - for example by vacuum on vapor, spraying on or non-electrical coating - on these islands and the exposed around these islands Applied to the substrate. The island material is then dissolved or chemically removed while the Electrode material surrounding the space of the island material in a shell-like manner - for example with the aid a soft brush or roller - by ultrasonic treatment or with high pressure gas or liquid streams Will get removed. The electrode material remaining on the substrate then forms the electrical grid.

It will largely be the view

argue that the ability of certain materials to form islands when deposited on a substrate is due to a certain mobility of the deposited atoms along the surface. Dabai has been found by various researchers that the tendency to form islands occurs very frequently with materials which have a relatively low melting point. It could, however, now also apply festgeäcellt that form the tendency islands, depends very strongly on the surface, on which the material in question is to applied v / ground. Examples of materials which form islands when blasted onto a rigid surface are indium, gallium, mercury, lead, cadmium, selenium and generally all other metals and alloys which have a low melting point. On less rigid surfaces, such as relatively soft, pliable elastomeric materials, such as those used in Ruticon elements, silver tends to form islands, even though silver has a relatively high melting point.

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This procedure was allowed

for example, an electric grid is made as follows uerdan: About a 4, u thick layer of one not sensitize Poly-H-Vinyl-Carbozole was made on a :! KtiSA glass substrate applied by dip coating. The element was then placed in a vacuum chamber and about a 1, u thick layer of selenium on the surface applied to the poly-n-vinyl carbazole layer, wherein the temperature of the NESA glass is relatively high, i.e. around 6g C was held. Under these conditions the selenium becomes brought down in the trigonal crystal form as an island structure. When exposed to coherent light observed v / earth that the spatial frequency structure of this Precipitation is very much concentrated around the spatial frequency characteristics of the island size. On this item was Then an electrode material is applied in a vacuum chamber,

ο
which consists of an approximately 2o A thick layer of chromium and

ο
then an approximately 3oo A thick layer of gold,

ο on which in turn a layer of indium about 100 Å thick is applied. In this context it should be mentioned that an insulating material or a photoconductor that differs from selenium could be applied over the Ir.seIstr-jC: door. The element was then removed from the vacuum chamber and immersed in an ammonium sulfide solution, creating the selenium islands have been chemically removed. The surface of the element was then brushed off with the help of a fine camel hair brush, whereby those parts of the electrode material were removed that previously covered the selenium islands. The item then became washed in distilled water and dried. The electric grid made in this way was found to be electrically continuous, with the open areas having a surface area of more than 95%. This grid showed no tendency to crack.

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Fig. 4 shows a reproduction

an electron photomicrograph of an electrical grid, which is produced by applying a metal layer on a selenium precipitate, this brine precipitate on a heated substrate. The selenium crystals are then removed in a chemical way. The individual gffungen have one Diameter of about ζ v / ei, u.

Other procedures can also be used

can be used to make such an electrical grid. For example, a continuous Metal layer are applied to a substrate, whereupon a laser or electron beam used to put the metal layer in certain places to evaporate, resulting in a porous electrical grid. Another method is that a suitable, itesque using an optical or electron beam is produced using a photoresist material as a starting material.

The buffer layers 18 and 2o

can consist of a material that is capable of to transport the charge carriers generated by the specific photoconductive insulating layer. Such Materials for the production of the buffer layers 18, 2o are, for example, poly-N-vinyl-carbazole, silicon, Germanium and selenium.

As mentioned earlier, the

Buffer layers designed so that they have good transport properties for load carriers. However, these materials must be either photosensitive or stress sensitive be. The purpose of these buffer layers is to keep the photo or voltage sensitive layer from penetrating of the electric field from the other side of the electric

509818/1149

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see grating through the openings to isolate. Such buffer layers are in particular in the frame of the present invention is very useful because the electric field lines a certain distance through the Openings of the electric grid from the side of the tall one Press the field into the area of the low field.

If desired, the _r

Buffer layer can also be omitted, with their Function is performed by the photoconductive layer, if made sufficiently thick. In this way it can be achieved that the activation radiation cannot reach the surface of the photoconductive layer carrying the electrical grid. Sine in about 4 .u strong layer of selenium can be used both as photoconductive Layer as well as a buffer layer against blue light on the opposite side of the electrical grid work because most of the light is already absorbed within the first, u.

If a good hole conductivity is desired, it can be advantageously used as Buffer material Poly-N-Vinyl-Karbozol can be used. A Buffer material, which has both good hole conductivity and good electron conductivity, is Poly-N-Vinyl-Karbozol, which with 2,4,7-trinitro-9-fluorenone is doped.

It could be determined

that when electrical grids are made from materials like chrome or aluminum on buffer materials like Poly-N-Vinyl-Carbozole and selenium is applied, the residual stresses within the metal mesh layer cause problems within the buffer layer leads. For example, if an electrical

S09818 / 11A9

scaes grilles made of chrome or aluminum on a poly-N-vinyl-carbzole layer is applied and then covered with another poly-N-vinyl-carbzole layer it follows that the residual stresses within the electrical grid layer lead to a break within the electrical grid. It is believed that the reason is that the solvent used for the preparation of the solution for the second poly-N-vinyl-carbazole layer causes the electrical The grid loses its adhesion to the first or lower poly-N-vinyl-carbazole layer. Those within the The stresses occurring in the metal grid layer are then sufficiently great to destroy the grid itself.

In the same way it was found that when an electrical grid was applied on a selenium layer using a photoresist method after a certain period of time the tendency prevails that the selenium is directly below the electrical Lattice layer crystallizes, but not in other areas. It is believed that this phenomenon is caused by the relatively high residual stresses within the metal mesh layer is caused. It should be mentioned that layers of various amorphous materials, such as selenium, under continuous Are exposed to stress of crystallization. Due to very thorough tests it was possible to show that in cases in which the electrical grid is exposed to relatively low residual stresses, what for example, by gold coating with subsequent coating with indium, those described above can be achieved Problems can be almost completely eliminated or minimized within wide limits. As a result, appears a composition including gold and indium for the manufacture of electrical grids in imaging elements very advantageous according to the invention. Self-

509818 / 1U9

ο Rural can also use more electrical materials Giving layer can be added to the specific properties highlight or suppress.

The voltage or current sensitive

Lich-j light modulation layer 24 can be made of a suitable Material exist which is able to produce _optical images in image-wise distribution of the photo-generated stresses or Record currents. Such materials are for example Elastomeric, liquid-crystalline materials, electro-optical Materials, for example Pockels ~ effect crystals and PLZT Ksraraik materials, electrophoretic materials, in which particles are charged in dielectric fluids, thermoplastic materials and moveable segment films, as described in J. Opt. Soc. Am., Vol. 9, No. 1o, pp. 22-25, 197o, and Opt. Acta, Vol. 16, p. 579, 197o.

The invention was hitherto made in

With regard to a generally designed image recording element according to FIG. 2. In the following now advantageous embodiments with reference to the further figures are described. It should be understood that various specific imaging elements according to of the invention require further elements in addition to the elements shown in FIG.

A particularly useful imaging element can be used within the scope of the present invention be built as a Ruticon element, whereby the voltage or current sensitive light modulation layer is a deformable Is elastomer. It should be understood that the term elastomer usually means amorphous materials which generate a restoring force depending on a deformation. Such amorphous materials result

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a force in the case of deformation, because the volume and surface forces have a tendency to return to their original shape before the force is applied. One detailed description of such a Ruticon element sicli results from US-PS 3,716,359.

Fig. 5 shows a Ruticon-

Image recording element according to the invention, in which a layer of conductive liquid serves as one of the electrodes. According to this figure is a conductive one Substrate 39 is provided, which in the case in question cius a thin transparent conductive layer 4o is made on a transparent glass substrate. 42 is applied. However, the substrate 39 can also be opaque if so desired. The photoconductive layer 1o, the buffer layers 13 and 2o, and the electrical grid 22 are designed similarly to the embodiment of FIG.

Above the buffer layer

a stress-sensitive light modulation layer is applied, which consists of an elastomer material. The light modulation layer 44 can be made of any elastomer material. Such Elastomer materials can be natural polymers in the form of natural rubber as well as synthetic polymers which have rubber-like properties, i.e. a certain elasticity. This includes materials v / ie Styrene butadiene, polybutadiene, neoprene, butyl, polysoprene, Nitrile and ethylene rubber. A beneficial type of Elastomer materials are water-based gelatine gels and dimethylpolysiloxane gels. The elastomer should be im generally be a relatively good insulator and one

4 Volume resistance value above 10 ohm-cm and

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have a shear modulus between 10 and 10 ^ dynes / cm ". Furthermore, the dielectric strength should be above 10 volts / mil. lie. Preferably the elastomer should

13th

a volume resistance value above 10 ohm-cm,

2 5 2

a shear modulus between 1o and 1o uyn / cm and one dielectric strength greater than 500 volts / mil. own. Commercially available Elastomers: Sylgard -132, Sylgard 184, Sylgard from Dow Corning Co., and RTV 6o2 and RTV 615 from General Electric Co. Elastomers having a higher volume resistivity value appear useful because they generally have better image storage capacity. Elastomers with relatively high dielectric strength also appear advantageous because they can be operated at relatively high voltages, which is usually desirable appears.

A particularly advantageous one

Elastomer is a transparent, very flexible composition made of an elastomeric dimethylpolylisoxangel which is obtained by mixing one part by weight of Dow Corning No. 182 silicone resin compound and between zero and 30 parts by weight of the Dow Corning No. 2oo dimethylpolysiloxane silicone oil. Change suitable resins are transparent, flexible organosiloxane resins, as described in US Pat. No. 3,284,4o6, where a larger part of the organ groups adhering to the silicon are methyl radicals.

The thickness of the elastomer layer

lies in the range between o, 1, u and 2ooo, u, where this Thickness depends, among other things, on the spatial frequency of the Information depends. Various optical properties of imaging elements can be enhanced by a suitable choice of the modulus of elasticity of the particular elastomer material is made. Using a

.BAD ORIGINAL

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relatively stiff elastomer results in irr. general removal of the electric field a more rapid recovery of an image so that the deletion can be carried out more quickly. Using an elastomer with a relatively low modulus of elasticity results in a lower resistance to strong deformations., consequently greater optical modulation is possible for a given value of an electric field.

The thick conductive liquid layer 46 can be either transparent or non-transparent be. Non-transparent conductive liquid layers are created with the help of mercury or at room temperature molten gallium-indium alloys. Transparent conductive liquids are, for example, water, which conductive impurities have been added. Using a transparent liquid should have a substantially different refractive index than that Have elastomer layer 44 so that deformations of the elastomer surface result in a phase modulation of the exposure light. A transparent liquid can also can be used to make a readout in reflection mode achieve, in which case reinforcement can be achieved by adding a thin flexible transparent layer is applied to the elastomer layer 44. Such a flexible transparent layer should generally be one strongly different refractive index both compared to the elastomer layer 44 and the transparent conductive Possess liquid.

According to Fig. 5 is also a

Window layer 48 is provided which is made of a suitable material - e.g. normal optical properties comprising glass - with which the conductive liquid layer 46 is in contact with the light modulation layer 44 can be held. However, it should be understood

5098 1 8 / 1U9

be that many conductive transparent liquids are generally in a direct current field of an electrolysis are exposed. This proves undesirable because it will destroy the elements of the imaging element due to gas formation. When operating a with a conductive liquid Image recording element is therefore usually a AC field at the elastomer buffer layer sandwich between the electrical grid and the conductive one Liquid prepared. It should be noted in this connection that the imaging element can also be used with one of the voltage source V caused DC voltage field and one caused by the voltage source V AC voltage field can be operated.

The function of the image recording element shown in Fig. Is as follows:

The voltage of the voltage source V is supplied to the electric grid and the substrate. The imaging element is then exposed to imaging radiation delivered either through the transparent substrate or through the window layer 48. However, if the substrate is oxaque, then the exposure must be through the window layer 48. The voltage of the voltage source V ₂ . is applied between the electrical grid and the conductive liquid layer 46. The electric field on the elastomer layer 44 is changed in a manner which corresponds to the imagewise irradiation

mechanical force of the electrical field on the elastomer layer causes a deformation, which continues until the forces of the electric field oppose it the surface tension and the elastic forces of the elastomer are balanced.

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At this point the deformation is interrupted and generally becomes stable as long as the electric field is maintained in the area of the elastomer. To that To delete the image / the field in the area of the elastomer is removed. The deletion takes place preferably by reversing the field on the elastomer, which increases the speed of erasure. Some photoconductors require a The fastest possible erasure is the irradiation of the photoconductor with a uniform activation radiation.

It should be noted that the deformations vary within the elastomeric material of which are within thermoplastic materials because elastomer deformations are independent of development steps heat treatment or softening with the aid of a solvent are during such treatment steps are generally necessary in connection with thermoplastic materials. Another difference between elastomers and thermoplastic materials is that in the former case the deformation for a certain field can reach a given limit value because the elastic forces oppose the deformation are. In the case of thermoplastic deformations, however, such a limit value occurs for a given field strength, as long as the thermoplastic material is kept in a soft state.

Although not in the drawing

is particularly shown, it should be understood that, according to an advantageous embodiment of the invention, a Line scrapes of the absorption type arranged between the projected imagewise radiation and the photoconductor of the ruticon is. A line scraping enables the elastomer layer to record images whose spatial frequencies are in the substantially lower than the resonance deformation frequency

509818/1 149

of the elastomer. The elastomer deforms in accordance of the pattern of the grating having a high spatial frequency in those areas in which a Irradiation takes place. The surface relief image on the Elastomer is made up of segments of the shadow of the grid. That which occurs when the deformed elastomer is irradiated The image consequently has a fine structure of lines which superimpose the originally recorded image are. If the line structure is disadvantageous, the same can be done with the aid of known optical filter methods removed.

In general it is advantageous to

the grid, for example a line grid, directly in to place the proximity of the photoconductive layer of the ruticon element. Other types of grids, such as those described in U.S. Patents 3,698,893 and 3,719,483, can also be arranged in this way. In some cases the electrical grid can be used as a carrier for the image information to serve. If the spatial frequency of the lattice structure is within the spatial frequency characteristic of the elastomer, the grid can serve as a screen. However, it is in general advantageous to use a screen in addition to the electrical grid. It should be noted in this connection that whenever appropriate, screens in the imaging elements can be used according to the invention.

Fig. 6 shows a Rutikon image recording

A drawing element according to the invention in which a layer of conductive gas serves as one of the electrodes. These The embodiment is essentially identical to that Fig. 5, except that the thick conductive liquid layer 46 of FIG. 3 is replaced by a conductive gas layer 5o, with an additional ionization of the gas Serving ionization element 51 is provided, which a

5 0 9 8 18 / 11A 9

may have transparent conductive window. The gas layer 5o can be a low pressure gas with a pressure of a few millimeters of mercury or with the aid of a low pressure arc discharge can be obtained by means of a glow discharge, the latter generally at a pressure of several, takes place u mercury. The gas can also be generated with the aid of an intense radiation source present in or in the region of the gas layer 5o or with the aid of radio frequency excitation of the gas located in the cavity or with the aid of other known methods for generating conductive gaseous plasmas. The elastomer surface 55 can also be charged if the gas layer 5o has a sufficiently high vacuum, with a source of thermally excited electrodes, for example a heated tungsten wire directed towards the elastomer surface, also being present. This electron source may be a guided electron gun beam, a non-guided electron beam, or a plurality of electron delivery sources. Above the layer 44, ie in the region of the intermediate surface between the layers 44 and 50, a reflective layer can additionally be provided.

Apart from the gas layer 5o

the image recording element according to FIG. 6 is identical to that of FIG. 5. It should be noted that the base electrode, which, as shown, consists of a transparent conductive layer 42 on a transparent carrier layer 4o, can optionally be opaque or transparent. In the embodiment shown in FIG., The gas layer 5o can be a Have a thickness between o, 1, u and infinite. The ionization element 51 may or may have a separate electrode be connected to a transparent conductive window, which serves to enclose the conductive gas above the elastomer layer 44. The one surrounding the conductive gas The container must naturally be airtight in order for the gas to flow on

509818 / 1U9

a certain negative pressure value can be maintained.

The embodiment shown in FIG. 6 is particularly suitable for holographic interferometry because the input light is passed through can be, whereby together with the exit light ' a composite image is formed. One holographic ο constructed image of an object can therefore with are superimposed on the actual image of the object, whereby interference ranks occur due to dimensional changes.

The one shown in FIG

Embodiment can be used in particular as a ruticon element which the electric field by means of a thin continuous conductor layer 54 on the surface of the Elastomer layer 44 is generated, wherein the conductive layer 54 is sufficiently flexible to the deformations of the elastomer layer 44 to follow. In the case where the conductive layer 54 is relatively highly reflective, the readout light is used with a high utilization factor. If the shift, however is opaque, the light transmitted through the substrate can be used to create a surface deformation image while light directed down from above can be used to reconstruct the image. the The light sources used can have different wavelengths and / or light intensities, with the additional There is a possibility that one light source is coherent and the other is non-coherent. Such an element can accordingly can be used to convert an image having a certain wavelength into an equivalent image with a different wavelength To convert wavelength. If the reading light radiated down from above has a significantly stronger intensity than that has image-forming light radiated from below, results

509818 / 1U9

the image recording element according to FIG. 7 is a very strong one Amplification of the image present on the input side, with the amplified light - for example for large areas Bildwit =: the> jabeschirme - can be used. That for The light used for reconstruction can also be coherent, i.e. with the help of a laser, so that the image processing takes place in the area of the surface deformation can, with the help of a non-coherent light from the left to generate an image. On the other hand, can the light forming the surface deformation may be coherent light, while the light used for reconstruction is not coherent in nature. The latter case appears to be more appropriate in general, because it is incoherent for light the human eye is more pleasant, while coherent light generators only light within a very narrow wavelength band, i.e. with a single color - for example red. One reason to use coherent light for the formation of the surface deformation image results in the case in which the reconstruction light for the image production takes place in connection with holograms. The image recording element according to the invention allows a 'holographically reconstructed image which by projection results in a surface deformation image, which with the help a non-coherent light of greater intensity, for example for large screens, can be coped with.

In this connection it should also be emphasized that the conductive substrate 39 can be either opaque or transparent. The thin conductive layer 54 should also generally be sufficiently flexible to follow the deformations of the elastomeric layer. If the conductive layer 54 is opaque, that is to say, for example, is a thin metal layer, the substrate 39 must be transparent in order to enable the image information to reach the photoconductive layer 16 . In this case, the image information

509818/1149

tion can be read out continuously if the reading light is fed in from above. If the conductive Layer 54, on the other hand, is transparent, the read light can be reflected on the surface. If that In contrast, substrate 39 is transparent, such an element can also be put into operation in transillumination will.

The conductive layer 54 can be made from a thin layer of a suitable metal or from a Combination of two or more metals exist. Such

ο layers of metal are between 50 and a few thousand A thick, The thickness depends, among other things, on the desired flexibility and the required conductivity. The conductive layer 54 can also be transparent, in which case, for example, a film of Dow Corning Resin ECR 34 on the surface the elastomer layer 44 can be applied. Other conductive layers can be used within the scope of the present invention can also be used. The voltage values between the electrical grid 22 and the thin conductive layer 54 for the formation and fixation of the deformation image are in the range between 1 and 250,000 volts, the Stress value depends, inter alia, on the thickness and other properties of the elastomer layer 44.

The conductive layer 54 has

generally has sufficient conductivity to obtain an equipotential surface, if a connection with an electrical power source is present. Furthermore, sufficient flexibility must be guaranteed, to follow the deformations of the elastomer layer 44. Furthermore, the fatigue resistance must be sufficiently high in order to be able to withstand the various and rapid formations and erasures of the surface deformations. In some

509818/1149

- 4ο

Cases is a strong opacity and reflectivity necessary if reading out with the aid of a strong Light source takes place, towards which the iotoconductive Layer is sensitive.

The conductive layer 54 is made

preferably made of gold and indium. Although the conductive layer 54 has been made using various methods - for example by chemical reaction, precipitation releases, electrophoresis, electrolysis, etc. - on the elastomer layer can be produced, it seems most expedient to to produce the conductive layer 54 by vacuum vapor deposition. A detailed description of the vacuum evaporation process for the production of metal layers including gold and indium layers on elastomer surfaces in U.S. Patent 3,716,359. In this connection it should be noted that other materials are added to the metal layers can be to a certain property - for example despectral reflectivity - to the corrosion resistance increase or decrease.

The image recording element ^ according to

Fig; 7 can also be a transparent insulating oil layer 56 have. In this way, the manufacturing requirements can be reduced. The presence of small holes within the elastomeric layer 44 can result in the imaging element of Figs. 7 receives a short circuit, possibly destroying its properties. The additional provision of an oil layer 56 prevents that Such short circuits destroy the properties of the element because the oil flows into such small holes can. Another property of the oil layer 56 is that its refractive index is different from that of air is. The provision of oil over the conductive layer 54

509818/1 U9

means that the light supplied from above is stronger al-j is modulated in the case of air. The reason for this is that to look for that for the same size of a Uberfläehendeformaticn the changes in the optical path are proportional to the refractive index of the medium in the range dex * Ot, v> rflache.

It should be understood that that

electrical grid in a very advantageous manner a strong increased frame storage time for that shown in FIG Element results because the elastomer layer 44 is very effective from the dark currents within the photoconductive layer 16 is electrically isolated over longer periods of time. The electrical insulation between the photoconductive layer 16 and the solar or current-sensitive light modulation layer in the area of the electrical grid is in image recording elements, such as ruticon elements, according to FIGS 6 and liquid crystal elements expressed all the more strongly, in which the readout light is generally up to the photoconductive Layer can come.

The electrical grille is at

Image-iuf-drawing elements according to the invention and also expedient to provide an electrical seal, according to which the electrical field during the desired exposure time of the photoconductive layer is supplied, whereupon the field is removed as soon as the loading ~ clearing is finished. However, the field applied to the elastomer layer or the other light modulation layer is maintained for a predetermined period of time during which image storage is desired.

Fig. 8 shows a cross-sectional view an image recording element according to the invention, which works in image subtraction mode, which one image is subtracted from the other. Furthermore, the relevant image recording element can be in the image threshold mode

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509818/1 U9

work, with soft only that part of an image above cvder recorded below a certain light intensity will. For reasons of simplicity, it is assumed that only photoconductive materials are used, which one have a single carrier polarity and absorb the incident activation radiation at a distance which is much smaller than the thickness of the layer.

As shown in Fig. 8, an is optional

Opaque or transparent conductive substrate 39 is provided, which according to the illustration consists of a transparent glass substrate 42 and a transparent conductive layer 4o applied thereon. Above of the substrate 39, buffer layers 58 and 6o are provided, between which an electrical grid 62 is arranged. Furthermore, a conductive insulating layer 16 and further buffer rails 64 and 66 are provided, between which a second electrical grid 6 8 is arranged. Finally, a voltage or current sensitive layer is located above the buffer layer 64 Light modulation layer 7o is provided. All of these individual elements are already associated with other figures have been described.

During the operation of such an imaging element, the photoconductive Layer 16 exposed to a first image, the voltages of the voltage sources VB and VC being set such that the charge carriers generated by the image from the photoconductive Layer 16 can be removed and fed through the electrical grid 62 to the buffer layer 6o. This gives an imagewise charge pattern within the photoconductive layer 16. The voltage of the voltage source VB then becomes reversed polarity and set to a value which is of the order of magnitude of the potential value of the photoconductive layer 16 is in the light areas of the first image.

50 98 18 / 1U9

The photoconductive layer 16

is then exposed to a second image pattern with the aid of activation radiation. The areas of the photoconductive layer 16 which did not receive any activation radiation in the first exposure and which now received radiation in the second exposure now generate charge carriers which are transported through the electrical grid 6 8, the electrical generated by the voltage source V _A Field is collapsed which was originally applied to the stress-sensitive light modulation layer 7o and the buffer layer 64. In the case where a current-sensitive light modulation layer is used, an image is formed with the aid of the current flowing through the buffer layer 6 4. The areas of the photoconductive layer 16, which have received a stronger radiation during the first exposure, are under a relatively strong opposing field, due to the volume charge error amounts. Within these areas, not as many photo-generated charge carriers can reach the electrical grid as in the areas of the photoconductive layer 16 which was exposed to a smaller amount of activation radiation during the first exposure. The charge carriers supplied to the buffer layer 64 thus represent a subtraction of the second image from the first image. It should be mentioned that it is not necessary to apply _{a voltage to the voltage source V A during the first exposure.} However, voltages from all three voltage sources must be applied during the second exposure.

The element shown in FIG

can also be operated in the image thresholding mode by making the second exposure spatially uniform, ie containing no image information. The voltage of the voltage source V _n is set so that only

509818/1 149

Areas of the photoconductive layer 16 which received light with an intensity below a certain value during the first exposure can supply charge carriers to the buffer layer 64. This results in a type of reversed threshold value in which only those areas of the imagewise activation radiation are recorded which had light intensity below a certain threshold value during the first exposure. In order to obtain the opposite type of threshold value, in which only those areas of imagewise exposure are recorded which have light intensities greater than a certain threshold value, the photoconductive layer 16 must first be exposed to a spatially uniform activation radiation, followed by using a suitable voltage value of the voltage source V imagewise activation irradiation is carried out in which only those areas of the photoconductive layer 16 can supply charge carriers to the buffer layer 64 which have received an activation radiation whose intensity is above a certain value of the imagewise exposure.

It should be mentioned that the Spannur.gs-

or current sensitive light modulation layer 7o made of any of the materials already described can. The images generated in the layer 72 can be read out or used in one of the ways described will.

The embodiment of the invention shown in FIG. 8 can be used in a wide variety of ways can be used by imaging elements previously described, including those which have a current or Have voltage-sensitive light modulation layer. The present invention, however, is in connection with stress sensitive Light modulating layers are particularly useful.

509818/1149

Image subtraction and image thresholding can be used for various types of optical processing. In the case of image subtraction, color masking and changes within the image can be determined. Threshold value applications are in the area of contrast enhancement and dynamic range expansion. The embodiment of the invention in question is particularly suitable for expanding the dynamic range , because highly intensive as well as weakly intensive image threshold values are possible, this being able to take place sequentially and additively on the same recorded image.

Fig. 9 shows a schematic

Sectional view of an image recording element according to FIG Invention, in which the electrical grid is covered with a conformally designed insulating grid. Such imaging elements have an increased Input sensitivity, which means that at the same Output characteristic a lower exposure radiation is necessary.

As shown in Fig. 9, an is optional

opaque or transparent conductive substrate 39 is provided, which, as shown, consists of a glass substrate and a transparent conductive substrate applied to it Layer 4o consists. Furthermore, an optical injection layer 72, the photoconductive layer 16, are buffer layers 74 and 76, an electrical grid 78 provided with a conformal insulating grid 79, as well as a voltage or current-sensitive light modulation layer 7o is provided. All of these elements are except for the injection layer 72 has already been described in connection with other figures.

509818/1149

It should be understood that the

The term "injection layer" means a layer which, when applied to a substrate or a conductor, for example a buffer layer or a photoconductive layer - an injection surface with respect to the one next to it Layer generated. An injection surface is included a surface that has a very light transition from the Allowed charge carriers between the adjacent layers, which transition may otherwise be relative can be difficult. In general, it appears advantageous to use an injection layer which is strong Has field-dependent charge carrier injection property. It could be found that a in a vacuum Chromium applied to a tin oxide-coated glass and then amorphous selenium also applied in a vacuum results in a good injection layer for electrons between selenium and chromium. It is also a certain amount of evidence present that a very strong field dependent injection of holes at the interface between the tin oxide coated Glass and poly-N-vinyl cabozole layers are made.

During the operation of a dex-like element, an electric field is created between the Substrate 39 and the electrical grid 78 generated by the voltage of the voltage source V is supplied. the Photoconductive layer 16 is then exposed to imagewise activation radiation exposed. The resulting photo-generated charge carriers move in the direction of the electrical Grid 78, at which point they come to adhere to the insulating grid 79. These load carriers are in the generally very shallow at the interface between the insulating grid 79 and the buffer layer 76 under formation of an image. As soon as a charge image has been created, i.e. the exposure is finished, the Voltage: the voltage source V, adjusted so that it

509818 / 1U9

- - 47 -

has an attractive effect on charge carriers, while the voltage of the voltage source V "is generally regulated downwards, so that the electric field generated thereby is of the order of magnitude of the field of charge carriers corresponding to the most exposed area of the input image. The photoconductive layer 16 is then exposed to uniform electromagnetic activation radiation, as a result of which charge carriers are generated over the entire surface. In those areas in which the input radiation was previously weakest, these charge carriers are _{attracted by the field of the voltage source V R} i ^{6 in the} direction of the electrical grid 78. As soon as the charge carriers are in the vicinity of the electric grid 78, the protuberances of the electric field of the voltage source V _A through the open areas of the grid cause the charge carriers to be drawn into the buffer layer 74, ie away from the insulating grid 79. In those areas in which the image irradiation was stronger, the field acting on the photo-generated charge carriers and the photoconductive layer 16 is lower because of the charge carriers adhering to the insulating grid 79. As a result, fewer charge carriers are moved in the direction of the electrical grid 78 and through it in these areas. In those areas in which the image irradiation was strongest, very little, or practically no charge carriers at all, are moved through the electrical grid 78, this being dependent on the value of the voltage of the voltage source V "

depends.

Which according to the picture pattern

Charge carriers held very flat on the insulating grid 79 consequently modulate the charge carriers caused by the uniform exposure generated charge carriers which reach the upper region of the image recording element on which Set the voltage or current sensitive light module

50981'8 / 1U 9

lation layer 7 ο affect. With sufficient more evenly Exposure can be much more imagewise distributed charge carriers at the interface between voltage or current sensitive The light modulation layer 7o and the buffer layer 74 are deposited as the amount which was first created in the photoconductive layer 16 by the input image irradiation. As a result, the element has an increased sensitivity.

In order to achieve an even greater sensitivity, a field-dependent Injection layer 72 may be provided. The injection layer has the tendency that the injection of charge carriers into the photoconductive layer 16 replenishes that removed during the uniform exposure Charge carriers enabled, resulting in a very strong increase in the imagewise carrier current. This is particular important in imaging elements which have, for example, one liquid crystal layer, in which case many Influences are not so much voltage-related, but current-related. It should also be mentioned that - if the intermediate layer between the injection layer 72 and the photoconductive layer 16 - a sufficiently low charge carrier injection threshold voltage a sufficient amount of charge carriers forming a reinforcement can be generated can without the procedural secret of a uniform Exposure would be necessary.

The embodiment of the invention shown in Fig. 9 is common to all types of described Image recording elements and is particularly suitable for those elements that are not so much a field-dependent, but rather have a current-dependent behavior, which is the case with some liquid crystal elements, for example Case is. In the case of a current-dependent behavior, the

Current-sensitive light modulation layer 7o naturally be able to conduct a charging current. It should be mentioned that the intensified charge image produced with the aid of such an element is an optical negative of the input image. Furthermore, some image thresholding operations are possible with such elements by influencing the voltage of the voltage source V _n .

Fig. 1o shows an embodiment

of the invention which has enhanced sensitivity. Referring to Figure 10, a schematic sectional view of an imaging member is shown shown, which in the area of the electrical grid 78 is a conformally designed photoconductive Has grid 8o. This photoconductive grid 8o consists of a photoconductive material, which is opposite to a different wavelength of the optical radiation is sensitive than as used for the photoconductive layer 16 will. The image recording element according to FIG. 10 has an increased sensitivity to optical input values .

During operation, the photoconductive grid 8o becomes an imagewise activation radiation exposed. The photo-optically generated charge carriers are drawn into the buffer layer 74 with the aid of the field of the voltage source V. The photoconductive grid 8o is thus electrically charged in an imagewise fashion. If then the photoconductive layer 16 of uniform activation radiation is exposed, the generated by the imagewise charge vertexation on the photoconductive grid 8o pulls Field the photo-generated charge carriers in the direction of the photoconductive grid. The greater the intensity of the input image at a certain position, the greater it is field generated by the image in this area, which in turn

18 / 1149- ·· '

- 5ο -

has the consequence that the number of charge carriers generated by the uniform irradiation and in the direction of the photoconductive grid 80 is pulled, the larger it is. As soon as these charge carriers reach the photoconductive grid 80 reach, they come under the influence of the field of the voltage source V, which through the open areas of the electrical and the photoconductive grid protrudes. As a result, there is a reinforcement of the buffer layer 74 supplied load carriers. If an optical injection layer 79 is additionally provided, the photoconductive Layer 16 along with the uniform exposure can be eliminated if at the interface between the buffer layer 76 and the injection layer 72 a sufficiently low injection threshold voltage is present. Of course Such an imaging element can be both photoconductive Layer 16 and an injection layer 72 have.

In those places where the

Part represented by the uniform irradiation generated by The charge carriers collected in the photoconductive grid 80 in proportion to the amount supplied to the buffer layer 74 Charge carrier is small, considerable imagewise formed currents arise within the buffer layer 74. Such an embodiment is particularly for image recording elements suitable, which have current-sensitive light modulation layers. It should be noted, however, that such elements are also capable of working, which are provided with stress-sensitive light modulation layers. It should also be emphasized that that the charge image generated in the buffer layer 74 is an optical positive of the input image supplied.

In Fig. 11, a further embodiment of the present invention is shown which an electrical grid, a grid consisting of electrically insulated strips, and an ortogonal grid made of electrically conductive

5 0 9 8 18/1 T 49 .;

capable strip has existing grid for a field-dependent charge injection. Such an image recording element results in a matrix-addressed storage and recording element / which has a voltage-sensitive light modulation layer possesses, however, such an element only carries out an image storage, as long as imagewise voltage is applied »Figure 12 shows the same imaging element in cross section.

According to FIGS. 11 and 12 there is

this image recording element is made of an insulating substrate 82, injection strip electrodes 84, a buffer layer 86, Strip grid electrodes 88, a buffer layer 9o, an electrical grid 92, a buffer layer 94, and a voltage-sensitive light modulation layer 96. During operation, the individual strips of the electrode sets 84 and 88 via conductors with a voltage source V-,

Yo

bound, the conductors 95 are also connected to a circuit. At those points at which the ortogonal conductive strips cross each other, the voltage _{generated by a voltage source V c} appears at the buffer layer 86. According to a special embodiment, the strip electrodes 84 have field-dependent carrier injection properties as soon as the voltage difference between the ortogonally crossing strips is sufficiently high is, charge carriers are injected from the overlapping area of a particular strip electrode 84 into the grid area near the substrate. These charge carriers move in the direction of the corresponding overlapping area of the strip electrodes 88, which lies between the buffer layers 86 and 9o. If the voltage of the voltage source V_ is sufficiently high, a substantial part of these charge carriers is transferred through the open areas between the strip electrodes 88 due to the voltage generated by the voltage source V_

'B

generated electric field attracted, so that this part up to

can reach the buffer rail 9o. The same load carrier are then due to the voltage of the voltage source V "

Sat

in the direction of the continuously laid out electrical grid 92, from where it is by means of a voltage source ν, generated electric field of the buffer layer 94 supplied from which they the stress-sensitive light modulation layer 96 change.

During the period during

which the voltage of the voltage source V- is maintained, these charge carriers remain at the interface between the buffer layer 94 and the voltage-sensitive light modulation layer 96, consequently the image is held in storage. The result is that the image recording element still maintains its storage capacity even when the imagewise voltage of the voltage source V is no longer supplied. In order to erase the image, the polarity of the voltage of the voltage source V _{A is} changed, as a result of which the charge carriers are removed from the buffer layer 94. It should be noted that this element has the property of producing gray tones. This means that a larger or smaller number of charge carriers can be injected into the various areas of the buffer layer 94, which has a corresponding influence on the relevant areas of the voltage-sensitive light modulation layer 96. Furthermore, it results that a different number of charge carriers can be injected into the different areas of the buffer layer at the same time. It must be emphasized, however, that only one picture element of the image is generated at a given point in time, this picture element lying in the region of the intersection of the strip electrodes 84 and 88, between which the voltage of the voltage source V is connected. The gray

scale of the picture element is determined by the size and / or Duration of the supply of the voltage of the voltage source V fixed-

placed.

The element shown in FIGS. 11 and 12 can additionally be one which is not shown Have a photoconductive layer disposed between the strip electrodes 84 and the buffer layer 86. With continuous exposure to an activating electromagnetic radiation, the photoconductive layer gives Charge carriers, thereby eliminating the need for the conductive strip electrodes 84 to have charge carrier injection properties own. However, it appears obvious that the embodiment shown in FIGS can be used in particular with elements which have stress-sensitive light modulation layers.

Fig. 13 shows a further embodiment of the invention in which the imaging element has acoustic image recording properties by providing a piezo-sensitive layer. Such a thing .Element is particularly useful for converting acoustic wave fields or acoustic images into optical images or holograms.

During the operation of such an element, acoustic wave fields pass through acoustic window 1oo and a thin conductive layer 1o2 on a piezo-sensitive layer 1o4, which is an imagewise Voltage excitation receives. The piezo-sensitive layer 1o4 can consist of a suitable piezo-electric or electrostrictive Material. Suitable piezoelectric materials are, for example, quartz, Rochell's salt, polarized PZT, ammonium dihydrogen phosphate, etc. Suitable electrostrictive materials are, for example, barium titanate, unpolarized PZT etc.

5 0 9 8 18/1149

A uniform activation radiation from an external source, not shown, is the photoconductive layer 16 is supplied, whereby charge carriers uniformly generated within this layer will. It should be noted that all of the layers on at least one side of the photoconductive layer 16 Activation radiation should be permeable.

The flow of charge carriers through

a buffer layer 1o8 in the direction of an electrical grid 1o6 is controlled by the bias voltage of a voltage source V and by the image-wise stress distribution within the piezo-sensitive layer 1o4 that is produced in accordance with the acoustic energy. In the case of a voltage source V _D

derived reference voltage is a low frequency voltage, whose frequency corresponds to that of the acoustic waves. This reference voltage has the same voltage distribution like a vertically applied acoustic reference beam. The stress distribution within the piezo-sensitive Layer 1o4 is therefore usually that of an acoustic hologram of an acoustically irradiated object.

It should be noted that the reference voltage of the voltage source V _ß can be provided optionally. With the correct polarity of the voltage V, the charge carriers generated by the uniform activation radiation in the photoconductive layer 16 are moved into the vicinity of the electrical grid 1o6, specifically in those areas in which the piezo-sensitive layer has received a large amount of acoustic energy and consequently a voltage is present with which the charge carriers can be moved in the direction of the electrical grid. These charge carriers pass through the electrical

509818/1 149

Lattice 1o6 in a buffer layer 11o, from where they undertake a modulation of a stress-sensitive light modulation layer 112.

It should be emphasized that the

embodiment shown in Fig. 13, in particular in Connection with elements, can be used which have a stress-sensitive light modulation layer. It should also be emphasized that such elements have the property of dynamic compression to a certain extent the acoustic information. Only a small number of load carriers are held by one pulled away any area of the photoconductive layer. A very heavily acoustically irradiated area of the Piezo-sensitive layer can therefore only be limited Number of charge carriers of the buffer layer 11o respectively. Given a sufficiently long acoustic irradiation, areas of the acoustic image can only be generate very small amounts of acoustic energy within the buffer layer 11o charge carrier amounts, which is comparable to the most heavily irradiated areas. Such generally appears desirable when converting acoustic to optical images. It should also be mentioned that the Low frequency voltage of the voltage source V is not absolutely necessary .. If it is present, it has recorded acoustic image the properties of an acoustic hologram.

Fig. 14 shows a further embodiment of the invention in which an electrical Grid is arranged within a xerographic element, which in connection with a xerographic copying process is usable. According to FIG. 14, a xerographic element 12p is provided which, in accordance with FIG Representation is a circular drum. This xerographic

see element 12o, however, can be in any configuration - For example in the form of a flat plate or an endless belt - be designed. The xerographic Element 12o is provided with a conductive substrate 122, a conductive layer 16, buffer layers 124 and 126 as well an electrical grid 125 is provided. In operation, the drum 12o is attached to an electrostatic charger 128 passed, which is provided with coronary discharge needles according to the illustration. However, it can another known charging device can also be used. At the coronary discharge needles is a high electric Potential of a high voltage, direct current or alternating current source applied, whereby charge carriers are applied to the outer surface of the drum 12o. The one on the Charge carriers applied to the surface of the drum 12o can optionally have a positive or negative polarity.

The electrostatically charged area

the drum surface is then moved past an exposure station, at which point a pattern of the image-wise activation radiation is emitted according to the image to be reproduced. The exposure station consists of a light source 13o, a transparency original 131, a lens 132 and a slit 133. However, the original to be reproduced can also be opaque, in which case the exposure is in reflection mode. The one reaching the photoconductive layer 16 imagewise Activation radiation creates an image-wise pattern of photo-generated charge carriers, which with the help of the voltage of a Voltage source V are attracted to the electrical grid 125. When the grid 125 approaches, the charge carriers arrive under the influence of the corona discharge the surface generated electric field, so that they can be supplied through the electric grid 125 and the buffer layer to the surface of the drum 12o on which

Place them to neutralize the surface charge carriers in an image-wise division, creating an electrostatic latent image is generated.

The electrostatic latent image

is then developed by supplying an electroscopic marking material in the form of a toner, which preferably has a charge of opposite polarity to the charge carriers on drum 12o. The toner material can be applied to the electrostatic latent image by means of the known cascade development method are, in which from a dispensing container 134 through individual intermediate elements toner particles of the surface of the Drum 12o are fed as it passes through the development station. However, it should be understood that any Development processes can be used to produce a visible image. For example, a Powder dusting process according to US Pat. No. 2,725,3o4, a magnetic brush process disclosed in U.S. Patent No. 2,975,758, or a liquid development process be used. The visible powder images are then fixed to the drum 12o or subsequently with the help of eLiSS suitable transfer method on a recording medium 136 - for example paper - transferred and fixed on the same. Though electrostatic latent images usually are developed with toner particles, the latent image can also be evaluated in other ways, for example electrostatic scanning systems can be used to read the latent image. The electrostatic image can can also be transferred to other materials using the TESI process and stored there.

If the xerographic element

12o is to be used for making additional copies, as is the case with recirculable xerographic Procedure is possible, must have any residual charge

509818/1149

on the drum before each repetition of the cycle after the visible powder image has been transferred to the recording medium. The residual charge can be removed from the drum surface by ionizing the air above the drum while the photoconductive layer is uniformly exposed. The voltage of the voltage source V _n is furthermore

Yo

adjusted so that photo-generated charge carriers can move in the direction of the electrical grid 125, from where they are with The residual charge can be drawn into the buffer layer 126 with the aid of the field. The charge removal can be, for example can be removed by means of an alternating current corona discharge in the presence of exposure to a light source. Preferably however, as previously shown, a conductive brush 138 is provided which is in direct contact with the drum surface is brought in the presence of an exposure. This method appears advantageous because toner particles remaining on the drum surface are removed at the same time. It seems understandable that the embodiment shown in FIG. 14 enables the use of photoconductors which are used in xerographic copiers have a strong dark decay characterxstics.

Pig, 15 shows a further embodiment of the invention in which two electrical grids are arranged within a xerographic element which can be used for xerographic copiers. 15, the xerographic element 14o consists of a conductive transparent substrate 142, buffer layers 146, 148, an electrical grid 15o therebetween, a photoconductive layer 16, buffer layers 152 and 154 , an electrical grid 156 between these layers, and an insulating layer 158.

509818/1 149

During operation, the

Photoconductive layer 16 in the area of an exposure station 129 exposed to imagewise activation radiation, the voltages of the voltage sources V- and V being set so that the resulting photo-generated charge carriers can be supplied to the buffer layer 146 and stored in the same. The polarity of the voltage source V " _A is then changed and the photoconductive layer 16 is exposed to uniform activation radiation with the aid of an exposure device 16o. The exposure device 16o consists of a light source 161 and a shield 162. At the same time, the surface potential of the surface of the drum 14o is changed, This can be achieved, as shown, by means of a fine conductive brush 164 which is brushed off the surface of the drum 140. However, this can also be achieved by using a conductive plate The reason for the lowering of the potential at the drum surface is to be found in the fact that in this way the charge carriers generated by the uniform exposure are brought through the electrical grid 156 onto the surface of the insulating layer 158 rden. This effect occurs imagewise, because the charge carriers removed from the photoconductive layer 16 during the exposure reduce the field on the photoconductive layer in the exposed areas. In this way, fewer photo-generated charge carriers can be removed from these areas during the uniform exposure.

Those adhering to the insulating layer

Charge carriers pull the toner particles onto the surface of the drum according to the desired image configuration. However, it is not disadvantageous if a relatively thin Trapping layer in the area of the interface between the

SQ. Μ 18> / Tt 4 9

- 6ο -

Buffer layer 154 and the insulating layer 158 is present. The insulating layer 158 may be any suitable electrical Insulating material - for example polyethylene, Tedlar, Teflon or Plexiglas - exist. This layer has a volume resistivity value above 1o ohm-cra, this being

12th

Resistance value is usually around 10 ohm-cm.

The embodiment shown in Fig. 15 is particularly for image subtraction and Image thresholding is suitable for precise control of the quality and properties of the xerographic image. For example, the contrast of an image can be changed with respect to a specific original to be copied. It can also be seen that this embodiment does not electrostatic charging device - for example corona charging device - needed to make copies. There is thus a substantial simplification of the copier configuration. It should be noted in this connection that in some cases in which the photoconductive layer 16 is sufficiently thick that the buffer layer 148, as previously mentioned, can be eliminated.

The ones on the different layers

voltages present in the various embodiments lie between 0.1 and 25000 volts, with the voltage value depending on the thickness of the layer in question and its properties etc. depends.

509818/1149

Claims (5)

Claims 1 . Electro-optical image capture -uilding element with a charge carrier generating layer, indicated that above the laduiigs carrier-generating layer (16) an electrical one Grid (22) is provided, which in turn is covered by a voltage or current-sensitive light modulation layer (2 4) is covered. 2. Imaging element after Claim 1, characterized in that a conductive substrate (14) is additionally provided. 3. Image recording element according to claim 2, characterized in that the substrate (14) is transparent. 4. Image recording element according to claim 2, characterized in that over the electrical grid (78) is provided with a conformally designed insulating grid (79) (FIG. 8). 5. Imaging element after Claim 2, characterized in that above the electrical grid (78) a conformally designed photoconductive Grid (8o) is provided (Fig. 9). 6. Image recording element according to claim 2, characterized in that in addition an injection layer (72) is provided in the area of the charge carrier generating layer (16) (FIG. 9). 509818/1 149 2438Ü63 7. Image recording element according to claim 2, characterized in that the Charge carrier generating layer (16) made of photoconductive Material. 8. image recording elements; inch Claim 7, characterized in that the electrical grid (22) is arranged on the surface of the photoconductive layer (16), and that the thickness the photoconductive layer (16) is chosen such that the on the opposite side of the photoconductive layer (16) directed activation radiation is essentially absorbed is before the same the interface between <ler photoconductive Layer (16) and the electrical grid (22) reached (Fig. 2). 9. Imaging element after Claim 7, characterized in that in the area of a surface of the photoconductive layer (16) a buffer layer (2o) is additionally provided (FIG. 2). 10. Image recording element according to claim 7, characterized in that the im A buffer layer (58, 66) is provided in each case in the area of the two surfaces of the photoconductive layer (16) (FIG. 8). 11. Imaging element after Claim 7, characterized in that a device is provided with which the voltage on the or current-sensitive light modulation layer (24) applied electrical field with a frequency spatially modulated which is within the spatial frequency response characteristic of the light modulation layer (24). 509818/1149 12. Image recording element according to claim 7, characterized in that the voltage or current sensitive light modulation layer (2 4) consists of an elastomer material. 13. Image recording element according to claim 12, characterized in that above the elastomer layer (44) a flexible conductive layer: (54) is provided (Fig. 7). 14. Image recording element according to claim 13, characterized in that an 01 layer (56) is provided above the flexible conductive layer (54) (FIG. 7). 15. Image recording element according to claim 12, characterized in that a layer (46) consisting of a conductive liquid is provided above the elastomer layer (44) (Fig. 5). 16. Image recording element according to claim 12, characterized dadurc h / that a layer (5o) consisting of a conductive gas is provided above the elastomer layer (44), and that an ionization element (51) is provided with which the conductive gas can be ionized (FIG. 6). 17. Image recording element according to claim 7, characterized in that the electrical grid is made of gold and indium. 18. Image recording element according to claim 7, characterized in that the voltage or current sensitive light modulation layer (2 4) consists of a liquid crystalline material. 509818/1149 - δ-4. 2431083 19.. Bilääufzeicftnuirgselement according to claim 7, characterized geke ti ή ζ e ί G h ti et '- _t that. -The voltage or current sensitive LiGhtmOdaiatioiisSchiit (24) made of an electro-optiähe material admits * 20. Biliä ^ f drawing oieitient according to claim 7, characterized ge ken a ζ ei G h η δ t, <äaß the electrical "Äitter (22) eihö spatial frequency is seated / which is outside of the rubbish Fr ^ cju ^ nz ^ Ähöhörscharakteristik the voltage or StromöHipfiftdlichen light modulation guarantee (24) %% - eqt » 21. Bil (äa \ äfzeiclifMngs © iteitterit according to claim 7, daduiröh geke η ö ζ ei G h % et that the area of at least one side of the electrical opener (22) is an anti-in ^ ectiöftäs-öhfiökfe precaution. 22. Ailotographed one of claims 1 hour iÄ 21, characterized ge h & ti h η is characterized in that däss ^ llje from a erstfeil elektriscihen grating (62) having on beidön Ö @ iteö liegöftden. PUfier & ^ kiöhten (58, 6o), a dairübelrliefeniöit fetal conductive sheet (16), a second electrical Öittör (68) Mt. ) consists (Mg. ii » 23. & ildatafzeichnungeeleme'ftt one of claims 1 to 21, characterized GEK e.'h η% ■ calibration net that the same from eifter fotoleitfähigeh layer (16), a darüberiiegendeh öfsten buffer layer (76), an electric grid (78), a compliant formed to photoconductive grating (79), an overlying second buffer layer (74) and a voltage or current sensitive light modulation layer (7o) consists (Fig. 9) > S03818 / 1U9 24.. Imaging element after one of claims 1 to 21, characterized in that g e k e η η show net that the same consists of an insulating substrate (82), a set of strip electrodes (84) arranged thereon, a first buffer layer (86) arranged thereover, a overlying set of strip electrodes (88), a second buffer layer (9o), an overlying one. Grid (92), a third buffer layer (9 4), as well as a tension or current sensitive light modulation layer (96). (Figures 11, 12). 25. Image recording element according to claim 24, characterized in that the first set of strip electrodes (84) is formed so that the same are capable of, under the influence of a electric field to inject charge carriers. 26. Image recording element according to claim 24, characterized in that above the first set of strip electrodes (84) a layer consisting of photoconductive material is arranged. 27. '' Imaging element after one of claims 1 to 21, characterized in that the same consists of an acoustic Window (1oo), a conductive layer (To2) arranged above it, a piezo-sensitive layer (1o4), an overlying photoconductive layer (16), an overlying first buffer layer (1o8), a electrical grid (To6), a second buffer layer (llo), as well as a voltage or current sensitive Light modulation layer (112) (Fig. 13). 5 0 9 8 18/1149 28. Xerographic imaging element according to one of claims 1 to 21, characterized in that the same consists of a conductive Substrate (122), an overlying photoconductive layer (16), a first buffer layer (124), an electrical grid (125) and an overlying second buffer layer (126). (Fig. 14). 29. Xerographic image recording element according to one of claims 1 to 21, characterized / in that the same is made of a conductive transparent substrate (142), an overlying first buffer layer (146), a first electrical grid (1.5ο), an overlying photoconductive layer (16), a second buffer layer (152, a second electrical grid (156), an overlying third buffer layer (154), and an insulating layer (158) (FIG. 15). 30. Image recording element according to claim 29, characterized in that above of the first grid (15o), a fourth buffer layer (143) is additionally provided. 31. The method according to claim 7, characterized characterized in that the following steps are provided: a) applying a first electric field to the charge carrier generating layer between the electric Grid and the conductive substrate, b) Exposing the charge carrier generating layer to an information-modulated, activating electromagnetic Radiation, and 509818/1149 c) Applying a second electric field to the voltage or current sensitive light modulation layer, whereby an image is generated within the same . · ^; ■■ '''■' - '' - - " . · '." - "- 32. "^;'·■' · ■ ^: '''" ^: - ■ ^ eriahren haeir entitlement: 7 / thereby · I deny η et V that the following ^ experience steps are carried out ·: - '''^>:"' · · '"' - ' · ■ "■ ---' ■■■ · '■ ■ ·' · ■ '-' ■ a) Applying an electrical field to the voltage generator current sensitive l b) Ztk -guide the in € © rinatiÖnsihödulated € iö see Strahltikg; with simultaneous application of a second elective height ^: i * oath on the charge carrier ¹ ^ generating view, and · c) Removal of the electric field ¥ 6n of the layer that generates charge carriers - _t whereby an image is generated within the voltage- 'or stfomefomefomefiapenseh Lichtitiodulationsschicht- *' 33.Procedure according to the Substralctions- mode according to claim 22, characterized by g e k e η η ζ e i c h η e t ^ that the following procedural steps are carried out: a) Applying a 'first electrical field between erase the conductive substrate and the iron Grid, b) applying a second electric field between the two electric grilles, c) exposing the photoconductive layer, a first image-wise pattern of the activating electromagnetic radiation, S09S1871 H-9 d) Reversing the polarity of the second electric field and setting the field strength to a value, which is substantially equal to the strength of the electric field within the photoconductive layer is in areas of high intensity irradiation, e) Applying a third electric field to the fourth buffer layer and the voltage and current sensitive Light modulation layer, and f) exposing the photoconductive layer to a second imagewise activation radiation, thereby creating within the light modulation layer an image corresponding to the second image pattern is generated, of which the first Image pattern is subtracted. 34. The method according to the threshold mode according to claim 22, characterized in that that the following procedural steps are carried out: a) applying a first electric field between the conductive substrate and the first electric grid, b) applying a second electric field between the two electric grids, c) Exposing the photoconductive layer to a imagewise pattern of activating electromagnetic radiation d) setting the strength of the second electric field to a predetermined value, e) Applying a third electric field to the fourth Buffer layer and the voltage and current sensitive Light modulation layer, and 509818 / 1U9 f) exposing the photoconductive layer to a uniform one Activation radiation, as a result of which an image is generated within the light modulation layer, which corresponds to those areas of the image-wise pattern of the activation radiation, the intensities below one have given value. 35. Procedure in accordance with the threshold value mode according to claim 22, characterized in that that the following process steps are carried out; a) applying a first electrical field between the conductive substrate and the first electrical grid, b) applying a second electric field between the two electric grids, c) exposing the photoconductive layer to a uniform one Activation radiation, d) setting the strength of the second electric field to a predetermined value, e) Applying a third electric field to the fourth buffer layer, and the voltage or current sensitive Light modulation layer, and f) exposing the photoconductive layer to an imagewise fashion Pattern of an activation radiation, whereby an image is generated within the light modulation layer, which corresponds to those areas of the image-wise pattern of the activation radiation, the intensities above have a given value. 509818/1 U9 - 7ο - 36. The method according to claim 22, characterized in that the following process steps be performed: a) applying a first electric field between the conductive substrate and the electric grid, b) Applying a second electric field to the second buffer layer and the voltage or current sensitive Light modulation layer, c) exposing the photoconductive layer to an imagewise pattern of activation radiation, d) Adjustment of the strength of the electric field, and e) exposing the photoconductive layer to uniform activation radiation, thereby creating an image is generated within the voltage or current sensitive light modulation layer. 37. Process reach claim 23, characterized in that the following process very it te be carried out: a) applying a first electric field between the conductive substrate and the photoconductive Layer, b) Applying a second electric field to the second buffer layer and the voltage or current sensitive Light modulation layer, c) exposing the photoconductive layer to an imagewise pattern of activation radiation, and 509818/1 149 d) exposing the photoconductive layer to a uniform one Activation radiation, whereby within the voltage or current sensitive light modulation layer an image is generated. 38. The method according to claim 24, characterized in that the following Process steps are carried out: a) Creation of a first electric field in certain areas between the strip electrodes and the Strexfengxtter electrodes, b) Generation of a second electric field between the strip grid electrodes and the electric field Grid, and c) generation of a third electric field within the voltage or current sensitive light modulation layer, whereby an image is created within it. 39. The method according to claim 26, characterized characterized in that the following process steps are carried out: a) exposing the photoconductive layer to uniform activation radiation, b) Generation of a first electric field in certain areas between the strip electrodes and the Strexfengxtter electrodes, 0 9 8 18/114 9 c) Generation of a second electric field between the strip grid electrodes and the electric field Grid, and d) Generation of a third electric field within the voltage or current sensitive light modulation layer , whereby an image is generated within them. 4o. Method for generating acoustic Pictures according to claim 27, characterized in that the following process steps are carried out: a) exposing the photoconductive layer to a uniform one Activation radiation, b) supply of information-modulated acoustic energy through an acoustic window, c) generation of a first electrical field between the conductive layer and the electrical grid, and d) generation of a second electric field within the voltage or current sensitive light modulation layer, whereby an image is created within it. 41. The method according to claim 4ö, characterized / that an additional one between the conductive layer and the electrical grid third electric field is generated, which has a frequency in the low frequency range. 509818/1149 42. The method according to claim 28, characterized in that the following process steps are carried out: a) applying ¹ an electrostatic charge to the surface of the imaging element, b) generation of an electric field between the conductive substrate and the electric grid, and c) exposing the photoconductive layer to an imagewise pattern of activation radiation, whereby an electrostatic latent image is formed. 43. The method according to claim 29, characterized in that marked that the following process steps be performed: a) Generation of a first electrical field between the conductive substrate and the second electrical field Grid, b) generating a second electrical field between the conductive substrate and the first electrical field Grid, c) exposing the photoconductive layer to imagewise Pattern of activating electromagnetic radiation, d) reversal of the polarity of the first electric field, e) exposing the photoconductive layer to uniform activating electromagnetic radiation and simultaneously changing the surface potential of the imaging member with respect to the 5 0 9 8 18/1149 Achievement of essentially earth potential, and f) applying electroscopic marking material to the imaging element, consequently to whose surface a visible image is generated. 50981 8 / 1U9 Blank page