阅读说明：本技术 用于e-纸的蒸汽阻挡层 (Vapor barrier for e-paper ) 是由 R·克勒卡 于 2017-06-13 设计创作，主要内容包括：一种e?纸组件，包括电荷响应可重写介质层和布置在介质层的第一侧上的空气传播电荷接收层。湿气阻挡层被插入在空气传播电荷接收层和电荷响应介质层的第一侧之间，其中湿气阻挡层包括无机材料。(An e-paper assembly includes a charge-responsive rewritable media layer and an air-propagating charge receiving layer disposed on a first side of the media layer. A moisture blocking layer is interposed between the airborne charge-receiving layer and the first side of the charge-responsive dielectric layer, wherein the moisture blocking layer comprises an inorganic material.)

1. A passive e-paper assembly comprising:

a charge-responsive rewritable dielectric layer including a first side and an opposing second side;

an airborne charge-receiving layer disposed on a first side of the dielectric layer; and

a moisture blocking layer interposed between the charge-receiving layer and the first side of the charge-responsive dielectric layer, wherein the moisture blocking layer comprises an inorganic material, and wherein the moisture blocking layer is for allowing migration of charge from the airborne charge-receiving layer to the charge-responsive rewritable dielectric layer.

2. The e-paper assembly of claim 1, comprising:

a counter electrode layer disposed on the second side of the dielectric layer.

3. The e-paper assembly of claim 1, wherein the inorganic material comprises at least one of an inorganic oxide material and a ceramic material.

4. The e-paper assembly of claim 1 wherein the moisture barrier layer has a thickness of about 1 to 1000 nanometers.

5. The e-paper assembly of claim 4 wherein the moisture barrier layer comprises about 10⁹A lower limit of resistivity in ohm-centimeters and including at least one of:

about 10¹³An upper limit of resistivity in ohm-cm; and

a breakdown voltage of less than about 20 volts.

6. The e-paper assembly of claim 1, comprising:

a first adhesion promoting layer interposed between the airborne charge-receiving layer and the moisture blocking layer; and

a second adhesion promoting layer interposed between the moisture blocking layer and the first side of the charge-responsive dielectric layer.

7. The e-paper assembly of claim 6, wherein at least one of the respective first and second adhesion promoting layers comprises at least one of:

a hybrid material comprising at least one inorganic functional group and at least one organic functional group; and

an organic polymeric material.

8. The e-paper assembly of claim 1, comprising:

a first adhesion promoting surface defined on a first side of the airborne charge-receiving layer, the first side facing the dielectric layer; and

a second adhesion promoting surface defined on the first side of the charge-responsive rewritable medium layer,

wherein at least one of the respective first and second adhesion promoting surfaces comprises a plasma modified surface.

9. The e-paper assembly of claim 1, wherein at least the airborne charge-receiving layer comprises an anisotropic structure to promote migration of charge to the charge-responsive dielectric layer.

10. A moisture barrier comprising:

an inorganic layer for interposing between the airborne charge-receiving layer and the first side of the charge-responsive rewritable dielectric layer of the flexible passive e-paper assembly, and wherein at least a portion of the inorganic layer allows migration of charge from the airborne charge-receiving layer to the charge-responsive dielectric layer.

11. The moisture barrier of claim 10, wherein the inorganic layer comprises a thickness of about 1 to 1000 nanometers, including about 10 nanometers⁹A lower limit of resistivity in ohm-centimeters and including at least one of:

about 10¹³An upper limit of resistivity in ohm-cm; and

a breakdown voltage of less than about 20 volts.

12. The moisture barrier of claim 10, wherein at least one of the charge-receiving layer and the charge-responsive dielectric layer comprises an organic material.

13. A method of manufacture, comprising:

providing a flexible passive charge-responsive rewritable dielectric layer of a passive e-paper assembly, the charge-responsive dielectric layer having a first side and an opposite second side; and

a charge-permeable moisture barrier layer is disposed on the first side of the charge-responsive dielectric layer, the moisture barrier layer comprising a flexible inorganic material.

14. The method of claim 13, comprising:

the moisture barrier layer is arranged to have less than about 1g/m at 38 degrees Celsius and 90% relative humidity²A Moisture Vapor Transmission Rate (MVTR) per week, a thickness of between about 1 and about 1000 nanometers; and

the moisture barrier is arranged to include about 10⁹A lower limit of resistivity in ohm-cm and including at least one of:

about 10¹³An upper limit of resistivity in ohm-cm; and

at least about 10¹⁴An upper limit of resistivity in ohm-cm while exhibiting a breakdown voltage of less than about 20 volts.

15. The method of claim 13, comprising:

an airborne charge-receiving layer is disposed on a side of the moisture barrier layer opposite the dielectric layer.

Background

Electronic paper ("e-paper") is a display technology intended to reproduce the appearance of ink on plain paper. Some examples of e-paper reflect light like plain paper and may be capable of displaying text and images. Some e-paper may be implemented as a flexible sheet like paper. One common e-paper implementation includes an e-reader.

Drawings

FIG. 1 is a side view that schematically illustrates an example passive e-paper assembly that includes a moisture barrier layer.

Fig. 2 is a side view schematically representing an example passive e-paper assembly such as in fig. 1 and further including a counter electrode layer.

Fig. 3 is a side view schematically representing an example passive e-paper assembly such as in fig. 2 and further including an adhesion promoting layer.

Fig. 4 is a block diagram schematically illustrating an example method of forming an inorganic moisture barrier layer.

Fig. 5 is a block diagram that schematically illustrates example methods and/or materials for forming an adhesion-promoting layer.

Fig. 6A is a diagram including a partial cross-sectional view schematically representing an example e-paper assembly and a side plan view schematically representing an example imaging unit.

Fig. 6B is an exploded view schematically representing an example passive e-paper display medium.

Fig. 6C is a top plan view schematically representing an example passive e-paper display medium.

Fig. 7 is a flow chart that schematically illustrates an example method of manufacturing a passive e-paper assembly.

Detailed Description

In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific examples in which the disclosure may be practiced. It is to be understood that other examples may be utilized and structural or logical changes may be made without departing from the scope of the present disclosure. The following detailed description is, therefore, not to be taken in a limiting sense. It is to be understood that features of the various examples described herein may be combined with each other, in part or in whole, unless specifically noted otherwise.

At least some examples of the present disclosure relate to providing a moisture barrier for a passive e-paper assembly such that a displayed image will be retained despite the presence of the e-paper assembly in variable humidity conditions. In particular, it is desirable to maintain satisfactory image quality regardless of where and/or the type of environment in which the e-paper assembly may be employed. In some cases, high humidity environments can pose challenging conditions for e-paper components without such moisture barriers. However, the inclusion of a moisture barrier layer in an example passive e-paper assembly may enable high retention even under such high humidity conditionsThe image quality. In some examples, the moisture barrier layer may enable the e-paper assembly to remain below about 0.1g/m at 38 degrees Celsius and 90% relative humidity²High image quality per Moisture Vapor Transmission Rate (MVTR) per day. Thus, via such an example moisture barrier, in some examples, the e-paper component may be passed through less than about 1g/m at 38 degrees celsius and 90% relative humidity²The moisture vapor transmission rate per week (MVTR) maintains high quality images.

In some examples, the e-paper component may sometimes be referred to as and/or incorporated within an e-paper display medium or an e-paper display device.

In some examples, a passive e-paper component includes a charge-responsive rewritable media layer including a first side and an opposing second side. An airborne charge-receiving layer is disposed on the first side of the dielectric layer, and a moisture blocking layer is interposed between the charge-receiving layer and the first side of the dielectric layer. The moisture blocking layer may comprise an inorganic material and is operative to facilitate the transfer of charge from the airborne charge-receiving layer to the charge-responsive rewritable medium layer.

The low permeability of the above-described example inorganic moisture barrier layers is in sharp contrast to at least some commercially available organic polymer materials that exhibit relatively high levels of permeability to water vapor, such that the relevant thickness of such organic polymers may be excessively (prohibitively) thick for use in flexible, passive e-paper display media (e.g., components). For example, the relevant thicknesses of at least some of those commercially available organic polymer materials that function well as moisture barriers may be on the order of tens of microns, which is substantially greater than the thicknesses of at least some of the example inorganic moisture barriers of the present disclosure. In some examples, in at least this context, the term "substantially larger" refers to a difference in thickness that is at least 25%, 50%, 75%, 100%, or even 2x, 3x, etc. difference. In some examples, in at least this context, the term "substantially larger" refers to a difference in thickness that is at least one (or at least two or three) order of magnitude different.

With this in mind, it will be understood that some example inorganic moisture barrier layers of the present disclosure may have an inherent moisture vapor transmission rate that is substantially less than the moisture vapor transmission rate of some such commercially available organic polymers. In some examples, in at least this context, the term "substantially less" refers to a difference in permeability that is at least 25%, 50%, 75%, 100%, or even 2x, 3x, etc. difference. In some examples, in at least this context, the term "substantially smaller" refers to a difference in permeability that is at least one (or at least two or three) order of magnitude different.

In some examples, the inherent relatively low permeability of the example inorganic moisture barrier layer allows the barrier layer to be relatively thin, which aids in flexibility of the e-paper assembly. In addition, this thinness in turn allows the use of inorganic materials with relatively large resistivity, with little or no degradation in image quality on the e-paper component.

In some examples, referring to the e-paper component as passive means that the e-paper component is electrically passive, i.e., without active electrode plates, electrode layers, drive electrodes, drive circuitry, etc., in order to intentionally cause a change in the image (e.g., information) displayed in the rewritable medium layer. Thus, in some cases, a passive e-paper component may sometimes be referred to as being circuit-free.

The passive e-paper display medium is relatively thin and light, at least in part because the example passive e-paper assembly has no on-board power supply and/or internal circuitry, thereby giving the example passive e-paper display a look and feel more like conventional paper.

In some examples, the passive e-paper component includes a counter electrode layer disposed on a second side of the dielectric layer.

In some examples, the passive e-paper assembly described above further includes a first adhesion promoting layer interposed between the airborne charge-receiving layer and the moisture barrier layer, and includes a second adhesion promoting layer interposed between the moisture barrier layer and the first side of the dielectric layer.

With such an arrangement, the charge-responsive rewritable medium layer is protected from moisture (e.g., humidity), so that the information displayed on the e-paper component maintains its image quality for an extended period of time despite the presence of moisture. It will be appreciated that such moisture protection is distinct from the general water resistance (resistance) of the charge-receiving layer, the counter electrode layer, the edges of the passive e-paper component, etc., such as when the e-paper component is temporarily exposed to spilled liquids, raindrops, etc. Further, in at least some examples, the e-paper assembly or other portions of the display device (e.g., the counter electrode layer, etc.) may provide a sufficient moisture barrier on the non-imaging side of the e-paper assembly, even if such layers are organic, because greater thickness is permissible and/or charge does not need to migrate through such layers in that particular location. Thus, in some examples, the inorganic moisture barrier layer interposed between the airborne charge-receiving layer and the charge-responsive layer may comprise the only inorganic moisture barrier layer of the e-paper assembly. In other words, the inorganic moisture barrier layer is located on the image side or surface of the e-paper component.

Robust preservation of image quality in passive e-paper display media (e.g., components) may enhance the ability of such passive e-paper display media to be used as gift cards, display cards, employee badges, guest badges, access badges, transaction media, and the like, under a wide variety of environmental conditions.

These examples and additional examples are described and illustrated in association with at least fig. 1-7.

Fig. 1 is a side view schematically illustrating an example passive e-paper assembly 20. In some examples, the e-paper assembly 20 may sometimes be referred to as an e-paper display assembly, an e-paper display medium, and/or an e-paper display device. Further, in some examples, the e-paper assembly 20 may form part of a larger e-paper display medium or display device, as shown later in association with at least fig. 6B-6C.

As shown in fig. 1, in some examples, passive e-paper assembly 20 includes a charge-responsive rewritable media layer 34, which media layer 34 includes a first side 35A and an opposite second side 35B. The airborne charge-receiving layer 30 is disposed on the first side 35A of the charge-responsive dielectric layer 34, and the moisture blocking layer 32 is interposed between the airborne charge-receiving layer 30 and the first side 35A of the charge-responsive dielectric layer 34. The moisture barrier layer 32 comprises an inorganic material and the moisture barrier layer 34 is used to transport charges (e.g., charges that are allowed to migrate) from the airborne charge-receiving layer 30 to the charge-responsive rewritable dielectric layer 34. The moisture barrier 32 includes a first side 33A and an opposing second side 33B.

In some examples, it will be understood that even in the absence of the charge-receiving layer 30 (in some examples), the charge-responsive dielectric layer 34 may be imaged by charge (e.g., fig. 6A), and that this layer 30 may be provided for protecting the charge-responsive layer 34 from inadvertent and/or malicious mechanical and electrical damage. However, in at least some examples of the present disclosure, the presence of charge-receiving layer 30 facilitates the creation and maintenance of high quality images at charge-responsive dielectric layer 34 in the manner described herein. In some examples, and as described further below, at least charge-receiving layer 30 may include an anisotropic structure to facilitate migration of charge on charge-responsive dielectric layer 34 (e.g., written by imager cell 310 in fig. 6A).

In some examples, the thickness and type of material forming the airborne charge-receiving layer 30 is selected to mechanically protect at least the charge-responsive dielectric layer 34 (including the microcapsules 308 shown in fig. 6A) from puncture, abrasion, bending, scratching, liquid hazards, crushing, and other impacts. Furthermore, in some examples, the airborne charge-receiving layer 30 may also protect the charge-responsive dielectric layer 34 from tribo (tribo) charges.

In some examples, because each layer 30, 32, 34 is relatively thin and highly flexible, the entire passive e-paper assembly 20 is flexible.

In some examples, referring the e-paper component to be passive means that the e-paper component 20 is electrically passive, i.e., has no active electrode plates, electrode layers, drive electrodes, drive circuitry, etc. to cause changes in the image (e.g., information) displayed in the rewritable media layer 34. Instead, any changes in the displayed image are caused by an external imaging unit, such as, but not limited to, an imaging unit described later in association with at least fig. 6A. Furthermore, as previously noted, the e-paper assembly 20 may be relatively thin and light in that it has no on-board power source.

The charge-responsive dielectric layer 34 includes components that switch color (e.g., black, white, etc.) when a magnetic field or charge is applied to the charge-receiving layer 30. In some examples, charge-responsive dielectric layer 34 includes a switchable pigment or die (die) combination. One example of such a charge-responsive dielectric layer 34 (in a passive e-paper assembly) is described later in association with at least fig. 6A. In some examples, the charge-responsive rewritable dielectric layer 34 includes a thickness (T3) between about 20 microns and about 100 microns. In some examples, charge-responsive dielectric layer 34 includes organic material(s).

With further reference to fig. 1, in some examples, the airborne charge-receiving layer 30 includes a thickness (T2) of between about 50 and about 200 microns and may include organic material(s). In some examples, the airborne charge-receiving layer 30 may include a UV curable acrylate, among other materials. In some examples, the airborne charge-receiving layer 30 may include additives, such as magnetite particles, to exhibit anisotropic properties to facilitate charge migration to the charge-responsive dielectric layer 34. Thus, in some such examples, the airborne charge-receiving layer 30 may sometimes also be referred to as an anisotropic layer.

In contrast, as previously noted, the moisture barrier layer 32 may comprise an inorganic material. Thus, in some cases, the moisture barrier layer 32 may sometimes be referred to as a non-plastic material and/or a non-glass material. In some cases, the moisture barrier 32 may sometimes be referred to as a non-metallic material.

In some examples, the inorganic material of the moisture barrier layer 32 includes an inorganic oxide material. In some examples, the inorganic oxide material may include alumina, titania, and/or silica, and in some examples may include similar metal oxide materials.

In some examples, the inorganic material of the moisture barrier layer 32 includes a ceramic material, such as, but not limited to, silicon nitride and/or the like.

As further shown in the diagram 200 of fig. 4, an inorganic layer (e.g., 32 in fig. 1-3) may be formed via one of a plurality 205 of implementations 210, 212, 214, 216, 218, 220, 222, 224, each of which is described further below. In particular, as shown in fig. 4, in some examples, the inorganic material may be formed and/or deposited via at least one of the curable liquid coatings 210; sputtering 212; evaporation 214; atomic layer deposition 216; chemical Vapor Deposition (CVD) 218; ion beam deposition 220; plasma assisted atomic layer deposition 222; and plasma assisted chemical vapor deposition 224.

In some examples, the moisture barrier layer 32 may exhibit less than about 0.1g/m at 38 degrees Celsius and 90% relative humidity²Moisture vapor transmission rate per day (MVTR). In some examples, the moisture barrier layer 32 may exhibit less than about 1g/m at 38 degrees Celsius and 90% relative humidity²Moisture vapor transmission rate per week (MVTR).

In some examples, such Moisture Vapor Transmission Rate (MVTR) may be achieved via a moisture barrier layer 32, the moisture barrier layer 32 having a thickness (T1 in at least fig. 1-3) between about 1 and about 1000 nanometers, and in some examples, a volume resistivity of about 10⁹Lower limit of ohm-cm and about 10¹³Between the upper limit of ohm-cm. In some examples, the lower limit of the resistivity exhibited by the inorganic moisture blocking layer 32 is sufficiently high to enable sufficient charge migration through the moisture blocking layer 32 (from the charge receiving layer 30 to the charge-responsive dielectric layer 34) to enable writing of high quality images on the charge-responsive dielectric layer 34 and to avoid image blurring. In some examples, the upper limit of the resistivity exhibited by the inorganic moisture barrier layer 32 is sufficient to avoid excessive charge accumulation on the outer surface (e.g., imaging surface) of the airborne charge-receiving layer 30. In some such examples, this upper limit reduces excessive charge buildup, which in turn can minimize or avoid inadvertent modification of the image (displayed on the charge-responsive media layer 32) that may occur during handling of the e-paper assembly 20 by a user if such excessive charge buildup exists.

In some examples, such as when the moisture barrier 32 has feetAt a sufficiently small thickness (such as on the order of sub-microns), the moisture barrier layer 32 may comprise about 10 a¹⁴Ohm-cm or at least about 10¹⁴Ohmic-centimeter resistivity, while exhibiting a breakdown voltage of less than about 20 volts in some examples. In some examples, the breakdown voltage may be slightly higher, such as 30 or 40 volts.

In some cases, about 10¹⁴Ohm-cm (or even at least about 10¹⁴Ohm-cm) may be at least one (or even two or three) orders of magnitude less than the resistivity of some commercially available organic materials that have sometimes been used to prevent moisture ingress. Such relatively large resistivity in those commercially available organic polymers may significantly impede migration of desired charges if one attempts to deploy the charges in a passive e-paper component, in accordance with at least some examples of the present disclosure.

In some examples, such as when the inorganic moisture barrier layer 32 may have a thickness (e.g., a maximum value in some examples) of about 1 micron, the inorganic moisture barrier layer 32 may include a dielectric strength of about 20 volts/micron (or less than about 20 volts/micron) such that the maximum surface charge (e.g., breakdown voltage) will be less than 20 volts. In one aspect, the breakdown voltage is equal to the thickness multiplied by the dielectric strength, where the dielectric strength may represent the maximum electric field that a material may experience before charge conduction begins to occur. In this regard, the breakdown voltage may represent the maximum voltage difference that a material may experience before charge conduction begins to occur. Via such an arrangement, it would be expected that the relatively thin structure and inherent properties of the inorganic material result in insignificant charge accumulation at the surface of the moisture barrier layer 32 and/or the charge-receiving layer 30. At least in this manner, excessive charge buildup and/or blooming (in some cases) may be avoided so that high quality image formation and/or retention may occur for the example passive e-paper assembly.

At least some such example arrangements of the moisture barrier layer 32 of the present disclosure are in sharp contrast to at least some commercially available organic materials (for moisture barrier layers) that have very high thicknessesResistivity (e.g. 10)¹⁸Ohm-cm) and typically at a thickness of at least about 10 microns while exhibiting a breakdown voltage of about 200 volts or greater than 200 volts. If one were to attempt to use such a commercially available arrangement for the moisture barrier layer 32, a surface charge build-up of about 200 volts (or more) would likely occur, which would interfere with high quality image retention associated with the unintended effect of such charges on the image at the charge-responsive dielectric layer 34 during handling of the e-paper assembly 20. In some cases, such an arrangement may result in blurring of the image at the charge-responsive dielectric layer 34.

In some examples, the moisture barrier layer 32 has a thickness (T1) of about 10 to about 500 nanometers. In some examples, the thickness (T1) is about 15 to about 300 nanometers. In some examples, the thickness (T1) is about 20 to 200 nanometers.

Although not shown for simplicity of illustration, it will be appreciated that in at least some examples, edges of the e-paper component 20 (e.g., edges of the respective dielectric layers, charge-receiving layers, counter electrode layers, etc.) are sealed against the ingress of moisture, whether in the form of a liquid and/or vapor.

In at least the example shown in fig. 1, the moisture barrier layer 32 is located inside the airborne charge-receiving layer 30 such that the relatively thin moisture barrier layer is structurally protected. In some such examples, the interior location may be relatively more effective for humidity protection than if the moisture barrier layer 32 were attempted to be placed outside of the airborne charge-receiving layer 32.

However, in some examples, the moisture barrier layer 32 may be located outside of the airborne charge-receiving layer 30. In some such examples, contact or handling of the e-paper component 20 (and in particular the moisture barrier 32) will be significantly minimized or completely eliminated in order to maintain the integrity of the moisture barrier 32. In some such examples, among the various inorganic materials from which the moisture barrier layer 32 may be formed disclosed herein, a more durable material may be selected when the moisture barrier layer 32 is located outside of the airborne charge-receiving layer 30. It will be further noted that in view of the relatively thin structure of the moisture barrier layer 32 and/or sufficiently similar resistivity properties of the moisture barrier layer (as compared to the charge-receiving layer 30), in some examples, such outer location of the moisture barrier layer 32 is believed to not significantly affect the performance of the airborne charge-receiving layer 30.

Fig. 2 is a side view that schematically illustrates an example passive e-paper assembly 50, which example passive e-paper assembly 50 includes at least some of substantially the same features and attributes as passive e-paper assembly 20 (fig. 1) except for further including a counter electrode layer 52.

Counter electrode layer 52 provides a counter electrode for imaging the e-paper display assembly by the imager unit (e.g., 310 in fig. 6A). In some cases, counter electrode layer 52 may sometimes be referred to as a ground electrode or ground electrode layer. In some examples, the counter electrode layer 52 includes a different conductive element 54 that acts as a ground electrode.

In this regard, the counter electrode layer allows counter charges to flow from the write module (e.g., imager cell 310 in fig. 6A) to the ground electrode. Thus, the e-paper assembly 50 (FIG. 2) remains substantially charge neutral despite the charge being emitted onto the airborne charge-receiving layer 30. Without a connection between the counter electrode layer 52 and the imager cell (e.g., 310 in fig. 6A), no appreciable amount of charge may be emitted onto the charge-receiving layer 30, and thus no information may be written to the charge-responsive dielectric layer 34.

In some examples, instead of having a different conductive element 54 in addition to the barrier layer 53, the counter electrode layer 52 may comprise a single element made of a transparent conductive material (such as indium tin oxide). In some examples, counter electrode layer 52 may include an opaque conductive material, such as when first side 25A may serve as a viewing side of e-paper display medium 50. In one example, the counter electrode layer 52 has a thickness (T4) between 5nm and 1 mm.

Fig. 3 is a side view that schematically illustrates an example passive e-paper assembly 60 that, in addition to further including first and second adhesion-promoting layers 62, 64, the example passive e-paper assembly 60 also includes at least some of substantially the same features and attributes as the passive e-paper assembly 20 (fig. 1) and/or the passive e-paper assembly 50 (fig. 2). In at least some examples, the first adhesion promoting layer 62 may enhance adhesion between the airborne charge-receiving layer 30 and the moisture blocking layer 32, and may enhance adhesion between the moisture blocking layer 32 and the charge-responsive dielectric layer 34.

As further shown in the diagram 250 of fig. 5, the adhesion promoting layer 265 (e.g., 60, 62 in fig. 3) may be formed via one of a plurality 255 of implementations 260, 262, 264, 268, 270, 272, 274, each of which is described further below.

In some examples, at least one of the respective first and second adhesion promoting layers 62, 64 may function like skin to prevent cracking and/or defects in the inorganic moisture barrier layer 32, such as may otherwise occur after formation of the inorganic moisture barrier layer 32 in some cases without one of the respective first and second adhesion promoting layers 62, 64.

In some examples, at least one of the first and second adhesion promoting layers 62, 64 may help to homogenize the non-uniform surface, which in turn may enhance adhesion relative to the inorganic moisture barrier layer 32. For example, in some examples, charge-responsive dielectric layer 34 may include a non-uniform surface. In some examples, the uneven surface may include capsules in an adhesive (e.g., fig. 6), which may exhibit an uneven surface resulting from aggregation of various materials thereof.

In some examples, at least one of the first and second adhesion promoting layers 62, 64 may promote adhesion (between the inorganic moisture blocking layer and one of the respective organic layers (30 or 34)) by acting as a bridge of mismatched chemistry (inorganic and organic) of the inorganic moisture blocking layer relative to the charge-receiving layer 30 or relative to the charge-responsive dielectric layer 34. In some such examples, at least one of the respective first and second adhesion promoting layers 62, 64 may include a hybrid (hybrid) material 262, as shown in the diagram in fig. 5. In some examples, the hybrid material includes at least one inorganic functional group and at least one organic functional group. In some such examples, the hybrid material may include an organosilane material, such as Tetraethoxysilane (TEOS), silsesquioxane, or the like.

In some examples, at least one of the respective first and second adhesion layers 62, 64 may include the organic polymer material 260 of fig. 5. In some examples, the organic polymer material may be flowable and curable, such as via heat or Ultraviolet (UV) radiation. For example, the polymeric material may include a UV curable acrylate, which may include some surface functional groups to promote adhesion to inorganic materials (such as moisture barrier layer 32).

In some examples, the first adhesion promoting layer 62 may be implemented as a surface defined on the first side 31A of the airborne charge-receiving layer 30 that generally faces the charge-responsive dielectric layer 34, and the second adhesion promoting layer 64 may be implemented as a surface defined on the first side 35A of the charge-responsive dielectric layer 34. In some examples, such first and second adhesion promoting surfaces 62, 64 may be achieved via plasma modification 264, as shown in the simplified diagram in fig. 5. For example, the surface defining the first side 31A of the airborne charge-receiving layer 30 may be chemically converted to an adhesion promoting surface to promote adhesion with respect to the first side 33A of the inorganic moisture barrier layer 32, and the surface defining the first side 35A of the charge-responsive dielectric layer 34 may be chemically converted to an adhesion promoting surface to promote adhesion with respect to the second side 33B of the inorganic moisture barrier layer 32, via exposure to a gaseous plasma.

In some examples, at least one of the first and second adhesion promoting layers (or surfaces) 62, 64 can be achieved via at least one of atomic layer deposition 266, chemical vapor deposition 268, surface silylation 270, plasma-assisted atomic layer deposition 272, and plasma-assisted chemical vapor deposition 274, as shown in the simplified diagram in fig. 5. In some examples, when tetraethoxysilane (and similar materials) is employed to form at least one of the first and second adhesion promoting layers 62, 64, an implementation via surface silanization may be used.

In some examples, the first and second adhesion promoting layers 62, 64 include a thickness (T5, T6) of less than about 50 microns. Thus, the relative thinness of the first and second adhesion promoting layers 62, 64 (or surfaces) helps minimize inhibition of (and/or helps promote) migration of charges from the airborne charge-receiving layer 30 to the charge-responsive layer 34, among other properties. Thus, in some examples, the moisture barrier layer 32 and/or the first and second adhesion promoting layers 62, 64 may exhibit such anisotropic behavior.

In some examples, at least one of the first and second adhesion promoting layers 62, 64, the inorganic material vapor barrier layer 32, and/or the airborne charge-receiving layer 30 may include an additive that imparts the ability to dissipate static charges. In some examples, such additives may be conductive particles or molecular additives. In some examples, such conductive particles have diameters in the range of tens of nanometers to tens of micrometers, and may come from several classes of materials. These materials may include metallic materials (such as silver), conductive oxide materials (such as indium tin oxide), inherently conductive polymer materials (such as polyaniline), or magnetic materials (such as magnetite).

Further, in some examples, the additive particles may be aligned in a magnetic or electric field to enhance conductivity in one direction (such as an out-of-plane direction). In some cases, a material or layer having such alignment may sometimes be referred to as being anisotropic. In some cases, a layer (e.g., the airborne charge-receiving layer 30) may enhance the migration of charges to the charge-responsive dielectric layer 34 by implementing an anisotropic structure.

In some examples, the molecular additive may include a quaternary ammonium salt. A quaternary ammonium salt may include tetrabutylammonium hexafluorophosphate.

In some examples, at least one of the first and second adhesion promoting layers 62, 62 may exhibit an adhesion between about 10⁹Lower limit of ohm-cm and about 10¹³Resistivity between the upper limit of ohm-cm. In some examples, such a range of resistivity applies to the thickness of the first and second adhesion promoting layers 62, 64 (T5 and T6) on the order of microns. In some examples, such a range of resistivities may be applicable to thicknesses on the order of tens of microns (T5 and T6).

However, in some examples, where the respective thicknesses (T5 and/or T6) may be on the order of at least several hundred microns, the respective first and second adhesion promoting layers 62, 64 may be implemented with an anisotropic structure as described above, such that migrating charges may readily flow out of plane (rather than in the plane of the charge receiving surface).

Via such resistivities and associated thicknesses of the respective first and second adhesion promoting layers 62, 64, such an arrangement may help prevent an amount of undesired charge accumulation on the surface of the charge-receiving layer 30 and/or an amount of lateral diffusion of undesired charge on the charge-receiving surface and/or as charge migrates from the charge-receiving layer 30 to the counter electrode layer 52.

In some examples, the inorganic moisture barrier layer 32 and/or the first and second adhesion promoting layers 62, 64 may be transparent or translucent. In some such examples, the airborne charge-receiving layer 30 may be omitted or may also be made transparent/translucent.

Fig. 6A is a diagram 301 including a cross-sectional view schematically representing an example e-paper assembly 300 and a side plan view schematically representing an example imager unit 310. In some examples, e-paper assembly 300 includes at least some of the substantially identical features and attributes of an e-paper assembly (e.g., 20, 50, 60), as previously described in association with at least fig. 1-5.

In some examples, the charge-responsive dielectric layer 334 of the e-paper assembly 300 provides one example implementation for the charge-responsive dielectric layer 34 of the e-paper assembly (e.g., 20, 50, 60), as previously described and illustrated with reference to at least fig. 1-3. As shown in fig. 6A, the e-paper assembly 300 includes an airborne charge-receiving layer 30, a moisture barrier layer 32, and a charge-responsive dielectric layer 334, wherein like reference numerals refer to like elements in fig. 1-3. It will be appreciated that in some examples, the e-paper assembly 300 may include the first and second adhesion promoting layers 60, 62 (fig. 3), but they are omitted from fig. 6A for simplicity of illustration.

In some examples, the outer surface 55 of the counter electrode layer 52 includes the viewing side 25B of the e-paper assembly 300, as represented by directional arrow V1. At the same time, the outer surface 31B of the airborne charge-receiving layer 30 provides the e-paper assembly 300 with a surface (e.g., an imaging surface) at which to apply an electrical charge.

As shown in fig. 6A, in some examples, charge-responsive dielectric layer 334 includes microcapsules 308 encapsulated by a resin or polymer 314. In one example, each microcapsule 308 includes black particles 310 and white particles 312 suspended in a fluid medium 316.

In some examples, when held in the viewing position, ambient light is transmitted through the transparent (or translucent) counter electrode layer 52, strikes the microcapsules 308, and is reflected back to the viewer V1. In the case where the white particles 312 of the microcapsule 308 are located near the counter electrode layer 52, the corresponding microcapsule 308 appears white to the viewer V1. However, when the black particles 310 of the microcapsule 308 are located near the counter electrode layer 52, the corresponding microcapsule 308 appears black to the viewer V1. The particles 310 and 312 have opposite charges. For example, the black particles 310 may be positively charged particles and the white particles 312 may be negatively charged particles such that when ions (e.g., positive or negative charges) are written into the charge-responsive medium layer 334, the respective particles 310, 312 respond according to a respective attractive or repulsive force. By varying the arrangement of alternating microcapsules, shades of gray can be produced, with white and black particles located near the counter electrode layer 52 to produce halftones (halftoning).

With this in mind, as further shown in FIG. 6A, the imager unit 310 includes an erase head 312 and a write head 314. In some examples, the respective heads 312, 314 may include ion-based techniques that generate charge from a corona and emit the charge in a selectable pattern to the charge-receiving layer 30 via an array of individually addressable electrodes. In some examples, other energy sources may be used to generate ions, such as positive and/or negative charges.

The imager unit 310 and the e-paper assembly 300 are arranged for movement relative to each other. For example, the e-paper assembly 300 may be movable relative to a stationary imager unit 310, or the imager unit 310 may be movable relative to the e-paper assembly 300 in a temporarily fixed position. The imager cells 310 are spaced from the outer surface 31B of the charge responsive layer 30 such that charge emitted from the imager cells 310 travels in air to the first side 31B of the charge responsive layer 30. In the particular example shown in FIG. 6A, the imager unit 310 is shown moving in direction A (when the e-paper assembly 300 is stationary) or the e-paper assembly 300 media is shown moving in direction B (when the imager unit 310 is stationary). During such relative movement, in some examples, the erase head 312 emits a plurality 318 of negative charges 319 onto the charge receiving layer 30 to erase any previous image retained by the dielectric layer 334. The write head (W)314 then emits a plurality 316 of positive charges 317 onto the charge receiving layer 30 in a selectable pattern (e.g., via an addressable electrode array). Generally, a sufficient amount of the charge 317 migrates through the charge-receiving layer 30 and through the moisture barrier layer 32 such that the charge affects the distribution of the black and white particles 310, 312 within the microcapsules 308 at selected locations of the array of microcapsules. In the example shown, because the black particles 310 are positively charged, they are repelled from the positive charge applied at the charge-receiving layer 30, while the white particles 312 (which are negatively charged) are attracted to the positive charge applied to the charge-receiving layer 30. As a result, the black particles 310 in the selected microcapsule 308 form an image viewable from side 25B, as represented by directional arrow V1.

In some examples, the surface 31B at the charge-receiving layer 30 may comprise the viewing surface/side of the e-paper assembly 300, as represented by directional arrow V2. Thus, in such an example, the charge-receiving layer 30 includes both the imaging side of the e-paper assembly 300 and the viewing side of the e-paper assembly 300.

In some examples, the black particles 310 may be negatively charged particles and the white particles 312 may be positively charged particles. In some such examples, the polarities of the respective erase and write heads 312, 314 of the imaging unit 310 may be reversed.

The microcapsules 308 exhibit image stability using chemical adhesion between particles and/or between particles and the microcapsule surface. For example, the microcapsules 308 may hold text and images indefinitely without using electricity, while allowing the text or images to be changed later.

In some examples, the diameter of each microcapsule 308 is substantially constant within layer 334, and in one example may be between 20 μm and 100 μm, such as 50 μm. In some examples, at least a portion of the counter electrode layer 52 may be composed of a transparent conductive material (such as indium tin oxide, or an opaque material).

The e-paper assembly 300 may have a variety of other configurations. In some examples, each microcapsule 308 may include black particles suspended in a white fluid. The black particles may be positively charged particles or negatively charged particles. One or more microcapsules form pixels of the black and white images displayed on the e-paper assembly 300. Black and white images are produced by placing black particles near the counter electrode layer 52 or away from the counter electrode layer 52 (when surface 55 is the viewing side-V1) or away from the charge-receiving layer 30 (when surface 31B is the viewing side-V2). For example, the microcapsules 308 with black particles 310 located away from the counter electrode layer 52 reflect white light corresponding to the white portions of the image displayed on the e-paper component 300 as observable on the first viewing side V1. In contrast, the microcapsules with black particles located near the counter electrode layer 52 appear black to the viewer V1, corresponding to the black portion of the image displayed on the e-paper display 300. Various shades of gray can be created by using halftoning, where the black particles are located near the counter electrode layer 52 or away from the counter electrode layer 52.

In view of these example implementations with respect to at least fig. 6A, in some cases, commercially available organic polymers may not be suitable for use with a moisture barrier layer (e.g., layer 32) because such commercially available organic polymers have very large volume resistivities, such as 10¹⁸Ohm-cm. If an attempt is made to use such a material as layer 32 in some of the example e-paper assemblies, a large accumulation of charge (emitted from imager cell 310 in fig. 6A) may accumulate on surface 31B of charge-receiving layer 30, rather than allowing such charge to migrate to charge-responsive dielectric layer 334. In the business of using suchIn some cases of the resulting organic polymer (instead of the exemplary inorganic moisture barrier layer), the combination of high resistivity and accumulation of charge on the surface (e.g., 31B) may cause lateral deflection of the incoming emitted charge (from imager cell 310), which may result in blurring of the image to be displayed via charge-responsive dielectric layer 334. Furthermore, in many such commercially available organic polymers, the surface of such layers may exhibit a relatively low surface resistivity, which in turn may cause charge (emitted from imager cell 310 in fig. 6A) to flow along the surface of the layer, thereby causing blurring of the image displayed via charge-responsive dielectric layer 334.

Fig. 6B is a diagram 401 including an exploded view schematically representing an example passive e-paper display device 40. As shown in fig. 6B, in some examples, display device 400 may include support members 440, 450, 460 formed around e-paper display 420 (e.g., e-paper assemblies 20, 50, 60, 300 in fig. 1-3, 6A) and/or fixed relative to e-paper display 420. In one aspect, such an arrangement may facilitate the use of the passive e-paper display 420 as a gift card, employee badge, display card, transaction medium, or the like. In some examples, one support member 460 includes a frame 464 formed around the passive e-paper display 420 and/or on an edge of the passive e-paper display 420. In some examples, the support member 460 may be further sandwiched (sandwich) between the first and second outer support members 440, 450, as shown in fig. 6B. The first outer support member 440 includes a frame 444, the frame 444 defining a window 446 holding a transparent member 447 through which the passive e-paper display 420 is visible and observable through the transparent member 447, as represented via the indicator symbol V1. The second outer support member 450 includes a frame 454, the frame 454 defining a window 456 through which a charge receiving layer (e.g., 30 in fig. 1-3, 6A) of the passive e-paper display 420 will be available for (accessible for) imaging via an imager unit (e.g., 310 in fig. 6A), as represented via indicator symbol I.

In securing the respective support members 440, 460, 450 relative to one another, the single e-paper display device 400 provides a relatively thin, flexible e-paper display medium that may be able to be robustly used and handled under a wide variety of conditions while maintaining a high quality image on the e-paper display 420. The e-paper display device 400 is configured to cooperate with an imager unit (e.g., 310 in fig. 6A) while still being usable and disposable like any ordinary gift card, identification card, access badge, etc. Accordingly, the e-paper display apparatus 400 is highly flexible, thin, light, and resistant to abrasion, impact, and the like. Furthermore, by including the moisture barrier layer 32 in the e-paper display 420 (e.g., fig. 1-3, 6A), the display device 400 may be subjected to high humidity conditions for extended periods of time without significantly affecting the image quality on the e-paper display 420.

Fig. 6C is a top plan view that schematically illustrates an example e-paper display device 470. In some examples, the e-paper display device 470 includes an e-paper assembly 480 supported via a support frame (e.g., 444 and/or 464 in fig. 6B). In some examples, the e-paper assembly 480 includes at least some of the substantially same features and attributes (e.g., 20, 50, 60, 400) as the example e-paper assembly, as previously described in association with at least fig. 1-6B. As represented in fig. 6C, the support frame is a non-imageable support frame because it does not implement the overwrite image in the manner previously described for the example e-paper assembly (20, 50, 60, 300). However, this does not preclude the support frame (e.g., 444) from carrying images (e.g., text, graphics, photographs) printed via non-e-paper techniques.

FIG. 6C also schematically represents at least some of the types of signals that may form portions of image 481 on e-paper assembly 480. For example, the image 481 may include text 482, such as an alphanumeric expression, such as a name, number, or the like. In some cases, the image 481 may include machine-readable indicia 484, such as a barcode or QR code. In some cases, image 481 may include a photograph 486 and/or a graphic 488.

It will be appreciated that in some cases, it may be desirable to maintain such information in image 481 in a clear, accurate manner for a sustained period of time. It will therefore be apparent that the introduction of the moisture barrier layer 32 (between the charge receiving layer 30 and the charge responsive dielectric layer 34 to prevent the ingress of moisture) can play an important role in high quality image retention, which in turn can improve the accuracy and readability of the displayed information. This performance may in turn contribute to the widespread, robust use of such passive e-paper media.

Fig. 7 is a flow chart that schematically illustrates an example method 500 of manufacturing. In some examples, method 500 may be performed via components, layers, structures, barrier layers, and/or the like as previously described in association with at least fig. 1-6C. In some examples, method 500 may be performed via components, layers, structures, barrier layers, etc., other than those previously described in association with at least fig. 1-6C.

As shown at 302 in fig. 7, method 500 includes providing a charge-responsive dielectric layer of a passive e-paper assembly. At 504, the method 500 includes disposing an inorganic moisture blocking layer on a first side of the dielectric layer, wherein the moisture blocking layer allows charge to migrate from an external location to the dielectric layer.

In some examples, the external location may refer to a location at which charge is emitted by an imager cell (e.g., 310 in fig. 6A) spaced apart from the charge-receiving layer, where such airborne charge is received by the charge-receiving layer through which the charge migrates before migrating through the moisture barrier layer to the (on the way to) charge-responsive dielectric layer. In some examples, when present on the opposite side of the moisture barrier layer, the charge also migrates through the adhesion promoting layer (or surface).

Further, in some examples, the method 500 of manufacturing may incorporate at least some of the features and attributes of components, layers, structures, barrier layers, and the like as previously described in association with at least fig. 1-6C. For example, some examples of methods of manufacture of passive e-paper components may include the characteristics and properties of materials and/or methods of forming moisture barrier layers and/or adhesion promoting layers as previously described in association with at least fig. 4-5.

Although specific examples have been illustrated and described herein, a variety of alternate and/or equivalent implementations may be substituted for the specific examples shown and described without departing from the scope of the present disclosure. This application is intended to cover any adaptations or variations of the specific examples discussed herein.