FILM WITH ELECTRICALLY CONTROLLABLE TRANSPARENCY AND METHOD FOR MANUFACTURING SAME

Disclosed are an electrically variable transmittance film and a method of manufacturing the same. The electrically variable transmittance film includes a base film, a first transparent electrode layer formed on the base film, a transparent non-conductive layer forming a pattern on the first transparent electrode layer, a variable transmittance layer formed on the transparent non-conductive layer, and including particles movable by an electric field, and a second transparent electrode layer formed on the variable transmittance layer.

TECHNICAL FIELD

An embodiment of the disclosure relates to a film with transmittance varying according to an external electrical signal and a method of manufacturing the same.

BACKGROUND ART

An electrically variable transmittance film is a film that can control the amount of transmitted light. The variable electrical permeability film may be constructed by inserting a variable transmittance layer having liquid crystal or suspended polarized particles between two opposing transparent conductive films. When an electric field is not applied to the particles, the liquid crystal or suspended polarized particles are irregularly arranged and scatter light, lowering transmittance. When an electric field is applied thereto, the particles are arranged regularly and the transmittance of light increases.

DISCLOSURE

Technical Problem

A technical objective to be achieved by an embodiment of the disclosure is to provide an electrically variable transmittance film that exhibits high transmittance through the movement of particles and allows variable uniform transmittance even in a large area, and a method of manufacturing the same.

Technical Solution

To achieve the technical objective described above, an electrically variable transmittance film according to an embodiment of the disclosure includes a base film, a first transparent electrode layer formed on the base film, a transparent non-conductive layer forming a pattern on the first transparent electrode layer, a variable transmittance layer formed on the transparent non-conductive layer, and including particles movable by an electric field, and a second transparent electrode layer formed on the variable transmittance layer.

To achieve the technical objective described above, a method of manufacturing an electrically variable transmittance film, according to an embodiment of the disclosure, includes forming a first transparent electrode layer on a base film, forming a variable transmittance layer including one or more particles on the first transparent electrode layer, and forming a second transparent electrode layer on the variable transmittance layer.

Advantageous Effects

According to an embodiment of the disclosure, a transmittance reduction problem due to an electrode may be addressed, and uniform transmittance variation is possible even in a large area. In another embodiment, a large-sized electrically variable transmittance film may be manufactured through a printing process.

MODE FOR INVENTION

Hereinbelow, an electrically variable transmittance film according to an embodiment of the disclosure, and a method of manufacturing the same, are described in detail with reference to the accompanying drawings.

FIG.1illustrates an electrically variable transmittance film according to a first embodiment of the disclosure.

Referring toFIG.1, the electrically variable transmittance film may include a base film100, a first transparent electrode layer110, a variable transmittance layer120, and a second transparent electrode layer130.FIG.1is a simple diagram of the cross-section of an electrically variable transmittance film to help understanding.

The base film100may be implemented by a film of a plastic material. For example, the base film may be implemented by polycarbonate (PC), polyethylene (PE), polypropylene (PP), polyvinyl alcohol (PVA), and the like. In addition, the base film100may be implemented by various transparent materials according to the related art that are not described in the present embodiment, and is not limited to a specific material. In another embodiment, the base film100may be implemented to be semi-transparent or may include a predefined color. For example, a film that transmit light and expresses a certain color may be implemented by adding a pigment to the transparent material forming the base film100. The thickness of the base film100may vary according to embodiments and may be implemented to be, for example, several micrometers (μm) to several millimeters (mm).

The first transparent electrode layer110may include a pattern including a conductive material. The conductive material forming the first transparent electrode layer110may include, for example, metal, indium tin oxide (ITO), or the like. The first transparent electrode layer110is not limited to the term used herein and may be implemented by not only a transparent conductive material, but an opaque or semi-transparent conductive material. A width w and a distance d of a pattern forming the first transparent electrode layer110may be variously implemented according to embodiments, and for example, the width may be implemented to be 3-30 μm and the distance may be implemented to be 30-300 μm. The pattern thickness of the first transparent electrode layer110may be variously implemented according to embodiments, and for example, the pattern thickness of the first transparent electrode layer110may be implemented to be 500 nm-50 μm.

The pattern formed in the first transparent electrode layer110may have a regular shape or an irregular shape. For example, the conductive pattern of the first transparent electrode layer110may be in a quadrangular pattern as illustrated inFIG.2or a honeycomb-shaped pattern. As the conductive pattern of the first transparent electrode layer110is used to adjust the transmittance of an electrically variable transmittance film by gathering one or more particles124existing in the variable transmittance layer120into one position when an electric field is applied thereto, the conductive pattern is not necessarily to have a regular shape, and may have an irregularly arranged shape with a narrow width according to embodiments. In the following description, a case assuming that the conductive pattern of the first transparent electrode layer110is regular as illustrated inFIG.2is described.

The variable transmittance layer120may include the particles124that are movable by an electric field. For example, the particles124may be particles having an electric charge (positive charge or negative charge) or a zeta electric charge. The variable transmittance layer120may be formed in various structures to guarantee movability of particles. For example, as in the embodiments ofFIGS.1and3, the particles124and334may be respectively included in a plurality of capsules122and332, or the particles may be included in a space formed by partition walls, as illustrated inFIGS.11and13. In addition, in order for the variable transmittance layer120to provide particle movability, various methods of forming a certain space may be applied to the present embodiment, and the disclosure is not limited to any one method. In the following description, to help understanding of the disclosure, inFIGS.1and3, a structure including capsules is described, and inFIGS.11and12, a structure including partition walls is described.

Referring back toFIG.1, the variable transmittance layer120may include the capsules122including one or more particles. The variable transmittance layer120may include a binder126to fix the capsules122between the base film100and the second transparent electrode layer130. Various types of the binder126according to the related art may be applied to the present embodiment, and the binder126may include a transparent, semi-transparent, or certain colored material.

Transmittance is adjusted through the movement of the particles124located between the first transparent electrode layer110and the second transparent electrode layer130. For the movement of the particles124, a space of a certain distance is needed between the first transparent electrode layer110and the second transparent electrode layer130. To secure a space between the two electrode layers110and130, a spacer such as a partition wall and the like, as illustrated inFIGS.11and12, may be arranged by a certain distance between the base film100and the second transparent electrode layer130. However, when a separate spacer is arranged, the structure becomes complicated, and as an additional process for forming a spacer is needed, manufacturing cost increases. Accordingly, in the present embodiment, the capsules122each having a certain volume is used to secure a space between the first transparent electrode layer110and the second transparent electrode layer130. The capsules122serve as a spacer supporting the space between the first transparent electrode layer110and the second transparent electrode layer130. In an embodiment, each of the capsules122may have a diameter of 10-100 μm, but the disclosure is not limited thereto. Also, after the second transparent electrode layer130and the like is coated, the capsules122may be pressed and formed into a disc shape. In this state, the capsule size may be set to have a height of 5-50 μm, but the disclosure is not limited thereto.

The capsules122exist between the base film100and the second transparent electrode layer130. Although the present embodiment illustrates, for convenience of explanation, that the capsules122, each being circular, are arranged in a row, the capsules122may exist irregularly between the base film100and the second transparent electrode layer130and may be arranged in multiple layers overlapping each other. Also, when a certain pressure is applied from the outside, the shape of the capsules122may be oval, not circular.

The capsules122may each include a capsule wall, the particles124, and the like. A dispersion material (e.g., oil and the like) exists in each of the capsules122. The dispersion material is a material that is not cured, and various materials according to the related art may be used as the dispersion material.

The particles124in each of the capsules122are particles having an electric charge affected by an electric field or a zeta electric charge according to an additive of the dispersion material. As the particles124are charged with the same type of an electric charge (e.g., positive charge or negative charge), unless an electric field is applied from the outside, the particles124are dispersed in the dispersion material in the capsules122. The shape of each of the particles124may be implemented in various shapes, such as a circular shape, a rod shape, or the like, according to embodiments.

The size of each of the capsules122may be variously implemented according to embodiments. In an embodiment, when an electric field is applied to the capsules122, for the particles124in each of the capsules122to be gathered well in a direction (or the opposite direction) of the conductive pattern of the first transparent electrode layer110, the size of each of the capsules122may be implemented to be greater than or equal to the distance d between lines forming the pattern of the first transparent electrode layer110. For example, when the distance d between the lines of the conductive pattern is 50 μm, the size of each of the capsules122may be implemented to be 50 μm or more. In another embodiment, the size of each of the capsules122may be implemented to be less than the distance d between the lines of the pattern.

The second transparent electrode layer130may include a conductive material and arranged above the variable transmittance layer120. The second transparent electrode layer130may include a transparent conductive material (e.g., ITO and the like). The conductive materials forming the first transparent electrode layer110and the second transparent electrode layer130may be the same as or different from each other according to embodiments.

In another embodiment, the materials for forming the base film100, the first transparent electrode layer110, the variable transmittance layer120, the second transparent electrode layer130, and the like may be selected such that a refractive index difference therebetween is minimized. For example, the first transparent electrode layer110and the second transparent electrode layer130may be implemented by ITO, and the base film100may be implemented by a material that minimizes a refractive index difference from ITO among various available materials. The minimization of the refractive index difference may minimize reflection and haze at an interface.

FIG.2illustrates an example of a pattern of the first transparent electrode layer according to an embodiment of the disclosure.

Referring toFIG.2, the first transparent electrode layer110may include a pattern of a conductive material. The distance d between the lines forming the pattern, the width w of the line, and the like may be implemented through various changes according to embodiments. A pattern of a metal material is formed on the base film100by a printing process (e.g., gravure printing, flexo printing, and the like) or a stamping and imprinting method, and thus, the first transparent electrode layer110may be formed. In this case, however, there may be shortcomings of transmittance reduction due to the metal material, resistivity reduction in a large area due to a pattern width limit, and a limit in identical driving over the entire area. As a method to address the above shortcomings, after printing (application) or coating ITO on the entire surface of the base film100, the first transparent electrode layer110of the conductive pattern may be formed through etching. The method of manufacturing an electrically variable transmittance film ofFIG.1is described again with reference toFIG.7.

FIG.3illustrates an electrically variable transmittance film according to a second embodiment of the disclosure.

Referring toFIG.3, the electrically variable transmittance film may include a base film300, a first transparent electrode layer310, a transparent non-conductive layer320, a variable transmittance layer330, and a second transparent electrode layer340.

As the base film300and the second transparent electrode layer340are the same as those of the first embodiment ofFIG.1, descriptions thereof are omitted.

The first transparent electrode layer310is formed on the entire surface of the base film300. The first transparent electrode layer310may include a transparent conductive material (e.g., ITO). For example, the first transparent electrode layer310may be formed by coating or applying a transparent conductive material to the base film300, or adhering a transparent conductive film (e.g., an ITO film) to the base film300. In addition, various methods according to the related art may be applied to the present embodiment.

The transparent non-conductive layer320may include a pattern formed of a non-conductive material on the first transparent electrode layer310. The thickness of the transparent non-conductive layer320may be variously implemented according to embodiments, and for example, the transparent non-conductive layer320has a thickness of 0.1-20 μm. The transparent non-conductive layer320is not limited to the term used herein, and the non-conductive material may be implemented by a transparent or semi-transparent material. For example, polymer, acryl, urethane, and the like may be used as the non-conductive material. In addition, various transparent or semi-transparent materials according to the related art, which are not described in the present embodiment, may be used as the non-conductive material forming the transparent non-conductive layer320and are not limited to a specific type.

While the conductive pattern ofFIG.1is an embossed form, a conductive pattern by the transparent non-conductive layer320ofFIG.3is an engraved form. The non-conductive pattern may be in a quadrangular shape as illustrated inFIG.4or a honeycomb shape as illustrated inFIG.5. In addition, the non-conductive pattern may have various shapes according to embodiments.

When electricity is applied to the first transparent electrode layer310and the second transparent electrode layer340, the strength of an electric field formed between the first transparent electrode layer310and the second transparent electrode layer340varies depending on the pattern shape of the transparent non-conductive layer320. For example, the strength of an electric field in a portion where a non-conductor exists and the strength of an electric field in a conductive pattern portion where a non-conductor does not exist are different from each other.

The variable transmittance layer330may include one or more particles334that are charged. In an embodiment, the particles334may exist in each of the capsules332. In other words, the variable transmittance layer330may include the capsules332, each including the particles334, and a binder336. When an electric field is applied, the particles334are gathered close to the first transparent electrode layer310exposed between the non-conductive patterns, and thus, transmittance is increased. When the electric field is removed, the particles334are moves away from each other by a repulsive force and distributed between the transparent non-conductive layer320and the second transparent electrode layer340, thereby lowering transmittance. The capsules332may serve as a spacer forming a certain distance between the transparent non-conductive layer320and the second transparent electrode layer340. As the capsules332and the like forming the variable transmittance layer330are the same as those of the first embodiment ofFIG.1, an additional description thereof is omitted.

The size of each of the capsules332may be variously implemented according to embodiments. In an embodiment, when an electric field is applied, in order for the particles334in the capsules332to be gathered well in one position, the size of each of the capsules332may be implemented to be the width w or more of the non-conductor of the non-conductive pattern. For example, when the width w of the non-conductor of the non-conductive pattern is 50 μm, the size of each of the capsules332may be implemented to be 50 μm or more. In another embodiment, the size of each of the capsules332may be implemented to be less than the width w of the non-conductor. When an electric field is applied, the particles334in each of the capsules332are moved from the non-conductive pattern to an etching portion (or an opposite direction) where the first transparent electrode layer310is exposed, and when the electric field is removed, the particles334in each of the capsules332are distributed by a repulsive force and dispersed in the capsules332. Transmittance varies according to the movement of the particles334in the capsules332.

In another embodiment, the materials for forming the base film300, the first transparent electrode layer310, the transparent non-conductive layer320, the variable transmittance layer330, the second transparent electrode layer340, and the like may be selected such that a refractive index difference therebetween is minimized. For example, the first transparent electrode layer310and the second transparent electrode layer340maybe implemented by ITO, and the transparent non-conductive layer320may be implemented by a material that minimizes a refractive index difference from ITO among various available materials The minimization of the refractive index difference may minimize reflection and haze at an interface.

FIGS.4and5illustrate an example of a pattern of a transparent non-conductive layer according to an embodiment of the disclosure.

Referring toFIGS.4and5, the pattern of the transparent non-conductive layer320may have a quadrangular shape or a honeycomb shape. The width w of the non-conductor forming the non-conductive pattern, the distance d (e.g., 3-15 μm) between the non-conductors, and the like may be implemented through various changes according to embodiments. The distance (i.e., an engraved pattern) between the non-conductors may serve as an electrode.

FIG.6illustrates another example of a pattern of a transparent non-conductive layer according to an embodiment of the disclosure.

Referring toFIG.6, a boundary610of a non-conductive pattern of a transparent non-conductive layer600may be implemented by an inclined surface. When each boundary610of the non-conductor forming the non-conductive pattern includes an inclined surface, a capsule630may be located closer to the first transparent electrode layer310, and thus, when an electric field is applied, particles in the capsule630may be gathered well in one position. In other words, by enlarging a direct/indirect contact surface between the capsule630and the first transparent electrode layer310, the strength of an electric field applied to the capsule630is increased so that the particles may be quickly moved.

FIGS.7and8illustrate a method of manufacturing the electrically variable transmittance film according to the first embodiment, according to an embodiment of the disclosure.

Referring toFIGS.7and8together, a first transparent electrode layer812having a certain pattern is formed on a baser film800(S700). For example, a transparent electrode material (e.g., ITO)810is printed or coated on the entire surface of the base film800and then etched into a certain shape, thereby forming the first transparent electrode layer812including a conductive pattern.

A variable transmittance layer820is formed on the first transparent electrode layer812(S710). The variable transmittance layer820may include capsules and a binder. A solvent in which a polymer forming a capsule wall along with charged particles is molten is mixed by a method such as agitation, vibration, or voltage application, thereby manufacturing a capsule including one or more particles. In addition, various capsule manufacturing methods according to the related art may be applied to the present embodiment. In another embodiment, the capsule may be already manufactured by various methods according to the related art. The variable transmittance layer820may be formed on the first transparent electrode layer812by a printing method, a coating method, or the like.

A second transparent electrode layer830is formed on the variable transmittance layer820(S720). A film of a certain thickness including a transparent conductive material is disposed on the variable transmittance layer820to form the second transparent electrode layer830, or the second transparent electrode layer830may be formed by coating or printing a conductive material on the variable transmittance layer820. In addition, various methods according to the related art may be applied to the formation of the second transparent electrode layer830. As an example, the second transparent electrode layer830may be formed by attaching an ITO film to the variable transmittance layer820. An optical transparent adhesive OCA and the like may be used for the attachment of the ITO film. In addition, various methods of attaching an ITO film according to the related art may be applied to the present embodiment.

FIGS.9and10illustrate a method of manufacturing the electrically variable transmittance film according to the second embodiment, according to an embodiment of the disclosure.

Referring toFIGS.9and10together, a first transparent electrode layer1010is formed on a base film1000(S900). The first transparent electrode layer1010is formed on the entire surface of the base film1000. For example, the first transparent electrode layer1010may be formed on the base film1000by applying various methods according to the related art, such as printing, coating, attaching, and the like.

When the first transparent electrode layer1010is formed, a transparent non-conductive layer1020is formed thereon (S910). The transparent non-conductive layer1020may include a non-conductive material of a certain pattern. For example, the transparent non-conductive layer1020having a certain pattern may be formed by forming a non-conductive material on the first transparent electrode layer1010in a pattern as illustrated inFIGS.4to5by a printing method or a stamping and imprinting method.

In an embodiment, when a non-conductive pattern is formed by an imprinting method, pressure is applied by using a roller with an embossed printing pattern to form the non-conductive pattern, and thus, a non-conductive material having a height less than the height of a non-conductive material of the non-conductive pattern may exist in a conductive pattern by the transparent non-conductive layer1020. Although, in the embodiments ofFIGS.3to5, the first transparent electrode layer310is exposed, as it is, in the conductive pattern portion formed by the non-conductive layer, in another embodiment, the embodiments ofFIGS.3to5may be implemented in the form in which a non-conductive material having a height less than the height of the non-conductive layer1020exists in the conductive pattern portion.

When the transparent non-conductive layer1020is formed, a variable transmittance layer1030is formed thereon (S920). The variable transmittance layer1030may include capsules and a binder. The variable transmittance layer1030may be formed by the same method as the variable transmittance layer forming method ofFIG.8.

When the variable transmittance layer1030is formed, a second transparent electrode layer1040is formed thereon (S930). The second transparent electrode layer1040may be formed by the same method as the second transparent electrode layer forming method ofFIG.8.

In another embodiment, before forming the variable transmittance layer1030, a process of etching a pattern boundary of the transparent non-conductive layer1020into an inclined surface may be further provided.

FIG.11illustrates an electrically variable transmittance film according to a third embodiment of the disclosure.

Referring toFIG.11, the electrically variable transmittance film may include a base film1100, a first transparent electrode layer1110, a transparent non-conductive layer1120, a variable transmittance layer1130, and a second transparent electrode layer1170.

As the base film1100, the first transparent electrode layer1110, the transparent non-conductive layer1120, and the second transparent electrode layer1170are the same as those of the second embodiment ofFIG.3, descriptions thereof are omitted.

The variable transmittance layer1130may include partition walls1140and capsules1150. Although, in the first embodiment ofFIG.1and the second embodiment ofFIG.3, a spacer such as a partition wall and the like does not exist and the capsules serve as a spacer, in contrast, in the present embodiment, the partition walls1140are provided to better withstand external pressure. The partition walls1140may include the same material as or a different material from the non-conductive material of the transparent non-conductive layer1120. In another embodiment, the partition walls1140may be added to the first embodiment ofFIG.1.

The partition walls1140may be arranged on the transparent non-conductive layer1120at regular intervals or irregularly. For example, the partition walls1140may be arranged in the same pattern (e.g., a quadrangular pattern or a honeycomb-shaped pattern) as the pattern of the transparent non-conductive layer1120with a width less than the width of the transparent non-conductor. The arrangement form, height, width, and the like of the partition walls1140may be variously changed according to embodiments. For example, each of the partition walls1140may be implemented to have a width of 5-30 μm and a height of 20-100 μm, and a distance between the partition walls1140may be implemented to be 20-100 μm. In another embodiment, the partition walls1140may be implemented in the form of having an inclined surface of 1-10° for stability, that is, the thickness of each partition wall increases downward from top to bottom.

The capsules1150including one or more particles1152that are movable by an electric field exist in a space partitioned by the partition walls1140. In an embodiment, the arrangement distance of the partition walls1140or the size of each of the capsules1150may be determined to include one capsule in each space partitioned by the partition walls1140. For example, one capsule1150may exist between the partition walls1140by implementing the partition walls1140such that the distance between the partition walls1140is greater than the diameter of one capsule and also less than the diameter of two capsules. When one capsule1150exists in each space partitioned by the partition walls1140, the particles1152in each of the capsules1150may be gathered well in one position by the conductive pattern that is engraved. In another embodiment, the arrangement distance of the partition walls1140or the size of each of the capsules1150may be determined such that the capsules1150exist in the space partitioned by the partition walls1140. In another embodiment, to fix the capsules1150, a binder as in the embodiments ofFIGS.1and3may be further included between the capsules1150.

An adhesive layer1160for attaching the second transparent electrode layer1170may be further provided between the second transparent electrode layer1170and the variable transmittance layer1130. The configuration of the adhesive layer1160may also be added the embodiments ofFIGS.1and3. The adhesive layer1160may include an optical transparent adhesive (OCA). In addition, various transparent adhesives according to the related art may be applied to the present embodiment.

FIG.12illustrates an electrically variable transmittance film according to a fourth embodiment of the disclosure.

Referring toFIG.12, the electrically variable transmittance film may include a base film1200, a first transparent electrode layer1210, a transparent non-conductive layer1220, a variable transmittance layer1230, and a second transparent electrode layer1270. The base film1200, the first transparent electrode layer1210, the transparent non-conductive layer1220, and the second transparent electrode layer1270may be configured as those described in the third embodiment ofFIG.11.

The variable transmittance layer1230may include ink1250, in which one or more particles1252are dispersed, and partition walls1240. The partition walls1240are used to form a certain space between the transparent non-conductive layer1220and the second transparent electrode layer1270, and is the same as that described in the third embodiment ofFIG.11. The ink1250including the particles1252that are movable by an electric field is injected between the partition walls1240. The ink1250is not limited to the term used herein, and may include various materials (e.g., oil and the like) that are not cured and have a certain viscosity so that particles may move. Furthermore, the ink1250may include a transparent or semi-transparent material or a material having a color.

An adhesive layer1260for attaching the second transparent electrode layer1270may be further provided between the second transparent electrode layer1270and the variable transmittance layer1230. The adhesive layer1260may include various transparent adhesives according to the related art, such as an optical transparent adhesive (OCA), and the like.

FIG.13illustrates a method of manufacturing the electrically variable transmittance films according to the third and fourth embodiments, according to an embodiment of the disclosure.

Referring toFIG.13, the first transparent electrode layers1110and1210are respectively formed on the base films1100and1200(S1300). The first transparent electrode layers1110and1210are respectively formed on the entire surfaces of the base films1100and1200. For example, the first transparent electrode layers1110and1210may be respectively formed on the base films1100and1200, by using various methods according to the related art, such as printing, coating, or the like.

When the first transparent electrode layers1110and1210are formed, the transparent non-conductive layers1120and1220are respectively formed thereon (S1310). The transparent non-conductive layers1120and1220may each include a non-conductive material in a certain pattern, as illustrated inFIGS.4and5. For example, a non-conductive material is formed on each of the first transparent electrode layers1110and1210in the certain pattern as illustrated inFIG.4or5by a printing method or a stamping and imprinting method, thereby forming the transparent non-conductive layers1120and1220.

In an embodiment, when an imprinting method is used, after coating or coating a non-conductive material on each of the first transparent electrode layers1110and1210, pressure is applied to the non-conductive material by using a roller having an embossed printing pattern, and thus, a transparent non-conductive layer having a certain pattern may be formed. For example, to form the non-conductive pattern ofFIG.4or5, the pattern may be generated by applying pressure to the non-conductive material by using a roller having a printing pattern (i.e., a pattern having an embossed conductive pattern formed by a non-conductive pattern) corresponding to the pattern ofFIG.4or5.

In another embodiment, the non-conductive pattern and the partition walls may be formed together through one-time imprinting. For example, a non-conductive material having a height greater than or equal to the height of the partition walls1140and1240is coated on or applied to the first transparent electrode layers1110and1210. As illustrated inFIG.14, by applying pressure to the non-conductive material using a roller having an embossed printing pattern corresponding to the partition wall and the non-conductive pattern, the partition walls1140and1240and the non-conductive pattern may be simultaneously generated. AlthoughFIGS.11and12illustrate that the first transparent electrode layers1110and1210are exposed, as they are, in the conductive pattern area formed by the non-conductive pattern, in another embodiment, the embodiments ofFIGS.11and12may each be implemented in the form in which a non-conductive material having a height less than the height of the non-conductive layer exists in the conductive pattern area.

When the transparent non-conductive layers1120and1220are formed, the partition walls1140and1240are respectively formed thereon (S1320). For example, as illustrated inFIGS.12and13, partition walls each having a certain height and width are formed.

When the partition walls1140and1240are formed, the variable transmittance layers1130and1230including particles that are movable by an electric field is formed between the partition walls1140and1240(S1330). For example, as illustrated inFIG.11, the variable transmittance layer1130may be formed by filling the capsules1150, each including the particles1152, between the partition walls1140, or as illustrated inFIG.12, the variable transmittance layer1230may be formed by injecting the ink1250including the particles1252between the partition walls1240.

When the variable transmittance layers1130and1230are formed, the second transparent electrode layers1170and1270are formed thereon (S1340). The second transparent electrode layers1170and1270may be formed by the same method as the second transparent electrode layer forming method ofFIG.8. In an embodiment, the adhesive layers1160and1260for attaching a transparent electrode film (ITO film) for forming the second transparent electrode layers1170and1270respectively to the variable transmittance layers1130and1230may be further provided.

FIG.14illustrates an example of a method of generating partition walls and a non-conductive pattern through one-time imprinting according to an embodiment of the disclosure.

Referring toFIG.14, a printing pattern1450may have various shapes according to the pattern of the transparent non-conductive layer and the pattern of partition walls1420. For example, when the electrically variable transmittance film as illustrated inFIG.12or13is manufactured, pressure is applied to a non-conductive material1410having a certain height and disposed on a base film1400by using a roller having the printing pattern1450that is embossed, and thus, the partition walls1420and the non-conductive pattern (i.e., an engraved conductive pattern) may be simultaneously formed.

A non-conductive material having a certain height may exist on a conductive pattern1430(hereinafter, referred to as the engraved pattern) that is engraved by the non-conductive pattern. For example, a non-conductive material having a certain thickness less than the thickness of a surrounding area may remain in the engraved pattern1430of the transparent non-conductive layer ofFIGS.11and12. When the partition walls1420and the engraved pattern1430are simultaneously formed by the pressure of a roller as in the method ofFIG.14, the non-conductive material may remain on the engraved pattern1430.

The electric field applied to the particles may be affected by the non-conductive material remaining on the engraved pattern. For example, when the resistance of the non-conductive material forming the transparent non-conductive layer is large, the electric field is not transferred to the particles through the engraved pattern, and when the resistance of the non-conductive material is too low, during voltage driving, the electric field is applied to the entire transparent non-conductive layer so that the particles are not gathered well in an engraved pattern portion.

In order for the electric field to be applied to the particles through the engraved pattern only, the surface resistance of the transparent non-conductive layer, the thickness of the non-conductive material remaining on the engraved pattern, the depth of the engraved pattern, and the like are considered. In other words, by adjusting at least one of the electrical resistance of the non-conductive material for forming the transparent non-conductive layer, the depth of the engraved pattern, and the thickness of the non-conductive material remaining on the engraved pattern, only the engraved pattern may operate as a conductive pattern for voltage driving.

In an embodiment, the non-conductive material of the transparent non-conductive layer may include a material having an electrical resistance of 10−7to 10−13Ω. In addition, the non-conductive material having electrical resistance in an appropriate range according to the thickness of the engraved pattern may be selected therefor.

In another embodiment, the thickness of the non-conductive material remaining on the engraved pattern of the transparent non-conductive layer may be set to be 50 nm to 10 μm. In particular, the thickness of the engraved pattern may be set to be 100 nm to 5 μm.

In another embodiment, the depth of the engraved pattern of the transparent non-conductive layer may be set to be 3-30 μm. In particular, the depth of the engraved pattern may be set to be 5-20 μm.