ELECTRONIC PAPER DISPLAY DEVICE AND MANUFACTURING METHOD THEREOF

An electronic paper display device includes a thin film transistor (TFT) array substrate, a light-transmitting substrate, a top electrode layer, a display medium layer, and a barrier layer. The top surface of the TFT array substrate has a bottom electrode layer. The light-transmitting substrate is located above the TFT array substrate. The top electrode layer is located on the bottom surface of the light-transmitting substrate. The display medium layer is located between the top electrode layer and the bottom electrode layer. The barrier layer is directly formed on at least one of the top surface and the bottom surface of the light-transmitting substrate. The barrier layer is in direct contact with the light-transmitting substrate, and is configured to resist moisture.

BACKGROUND

Field of Invention

The present disclosure relates to an electronic paper display device and a manufacturing method of the electronic paper display device.

Description of Related Art

In a market with a wide variety of consumer electronic products, electronic paper display devices have been extensively utilized as display screens. The display medium layer of the electronic paper display device mainly consists of microcapsules having black and white particles. By applying a voltage to the display medium layer, the black and white particles can be driven to move so as to display a black color, a white color, or a gray level. Since the electronic paper display device uses incident light to irradiate the display medium layer to achieve the purpose of display, the electronic paper display device does not need a backlight source, and can save power consumption.

Generally speaking, an electronic paper display device are formed by stacking multi-layer structures, and in order to prevent water vapor from entering, a protective sheet having a moisture barrier layer can be disposed on a front panel laminate (FPL), and an optical clear adhesive (OCA) is used to adhere the protective sheet having the moisture barrier layer to the front panel laminate. Due to the large number of stacked layers of the traditional electronic paper display device, it is difficult to reduce the overall thickness and material cost of the electronic paper display device, and the stacking of multi-layer structures also makes it difficult to improve optical transmittance, which affects the user experience and is not conducive to product competitiveness.

SUMMARY

One aspect of the present disclosure provides an electronic paper display device.

According to some embodiments of the present disclosure, an electronic paper display device includes a thin film transistor (TFT) array substrate, a light-transmitting substrate, a top electrode layer, a display medium layer, and a barrier layer. A top surface of the TFT array substrate has a bottom electrode layer. The light-transmitting substrate is located above the TFT array substrate. The top electrode layer is located on a bottom surface of the light-transmitting substrate. The display medium layer is located between the top electrode layer and the bottom electrode layer. The barrier layer is directly formed on at least one of a top surface and the bottom surface of the light-transmitting substrate, wherein the barrier layer is in direct contact with the light-transmitting substrate, and is configured to resist moisture.

In some embodiments, the barrier layer is directly formed on the top surface of the light-transmitting substrate, and the top electrode layer is directly formed on the bottom surface of the light-transmitting substrate.

In some embodiments, the bottom surface of the light-transmitting substrate has a functional area extending outward from the display medium layer, and the top electrode layer extends to the functional area.

In some embodiments, a top surface of the barrier layer is exposed.

In some embodiments, the barrier layer is directly formed on the bottom surface of the light-transmitting substrate, and the top electrode layer is directly formed on a bottom surface of the barrier layer, such that the top electrode layer is in direct contact with the barrier layer.

In some embodiments, the bottom surface of the light-transmitting substrate has a functional area extending outward from the display medium layer, and the barrier layer and the top electrode layer extend to the functional area.

In some embodiments, the top surface of the light-transmitting substrate is exposed.

In some embodiments, a sidewall of the light-transmitting substrate, an edge of the barrier layer, and an edge of the top electrode layer are aligned with each other in a vertical direction.

In some embodiments, an edge of the display medium layer is recessed from a sidewall of the light-transmitting substrate so that the light-transmitting substrate has a protruding portion, and the electronic paper display device further includes a sealant located between the protruding portion of the light-transmitting substrate and the TFT array substrate, and the sealant surrounds the display medium layer.

In some embodiments, the sealant is in contact with a bottom surface of the top electrode layer.

In some embodiments, the sealant extends to a lower portion of the sidewall of the light-transmitting substrate, such that an upper portion of the sidewall of the light-transmitting substrate is exposed.

In some embodiments, the display medium layer includes a plurality of microcapsules or a plurality of microcups, and each of the microcapsules or each of the microcups has charged particles with different colors.

According to some embodiments of the present disclosure, an electronic paper display device includes a thin film transistor (TFT) array substrate, a light-transmitting substrate, a top electrode layer, a display medium layer, and a sealant. A top surface of the TFT array substrate has a bottom electrode layer. The light-transmitting substrate is located above the TFT array substrate. The top electrode layer is located on a bottom surface of the light-transmitting substrate. The display medium layer is located between the top electrode layer and the bottom electrode layer, wherein an edge of the display medium layer is recessed from a sidewall of the light-transmitting substrate so that the light-transmitting substrate has a protruding portion. The sealant is located between the protruding portion of the light-transmitting substrate and the TFT array substrate, surrounds the display medium layer, and extends to a lower portion of the sidewall of the light-transmitting substrate.

In some embodiments, the electronic paper display device further includes a barrier layer directly formed on a top surface of the light-transmitting substrate.

In some embodiments, the electronic paper display device further includes a barrier layer directly formed on the bottom surface of the light-transmitting substrate, wherein the top electrode layer is directly formed on a bottom surface of the barrier layer, such that the top electrode layer is in direct contact with the barrier layer.

One aspect of the present disclosure provides a manufacturing method of an electronic paper display device.

According to some embodiments of the present disclosure, a manufacturing method of an electronic paper display device includes directly forming a barrier layer on at least one of a top surface and a bottom surface of a light-transmitting substrate, wherein the barrier layer is in direct contact with the light-transmitting substrate, and is configured to resist moisture; forming a top electrode layer on the bottom surface of the light-transmitting substrate; forming a display medium layer on the top electrode layer on the light-transmitting substrate; and disposing the light-transmitting substrate and the display medium layer on a thin film transistor (TFT) array substrate, such that the display medium layer is located between the top electrode layer and a bottom electrode layer of the TFT array substrate.

In some embodiments, the top electrode layer is directly formed on the bottom surface of the light-transmitting substrate.

In some embodiments, the barrier layer is directly formed on the bottom surface of the light-transmitting substrate, and the top electrode layer is directly formed on a bottom surface of the barrier layer, such that the top electrode layer is in direct contact with the barrier layer.

In the aforementioned embodiments of the present disclosure, since the top electrode layer of the electronic paper display device is located on the bottom surface of the light-transmitting substrate, and the barrier layer is directly formed on at least one of the top surface and the bottom surface of the light-transmitting substrate, the light-transmitting substrate on which the top electrode layer and the barrier layer are disposed has the functions of conducting electricity and blocking water vapor, and can replace an upper substrate of a front panel laminate (FPL) and an overlying anti-moisture protective sheet of a traditional electronic paper display device, and can further omit an optical clear adhesive (OCA) used to attach the upper substrate and the protective sheet. As a result, the electronic paper display device of the present disclosure can effectively reduce the number of stack layers. Compared with the traditional electronic paper display device, the electronic paper display device of the present disclosure can reduce the height of the water blocking zone between the top surface of the TFT array substrate and the barrier layer by 20%, and thus the expected amount of moisture intrusion is reduced by 20% to improve the reliability of the electronic paper display device. In addition, such a configuration can reduce the overall thickness and material cost of the electronic paper display device, and can improve optical transmittance, which are beneficial to user experience and product competitiveness.

DETAILED DESCRIPTION

FIG.1is a cross-sectional view of an electronic paper display device100according to one embodiment of the present disclosure. As shown inFIG.1, the electronic paper display device100includes a thin film transistor (TFT) array substrate110, a light-transmitting substrate120, a top electrode layer130, a display medium layer140, and a barrier layer150. A top surface111of the TFT array substrate110has a bottom electrode layer112. The top electrode layer130is a common electrode, and the bottom electrode layer112is a pixel electrode. The light-transmitting substrate120is located above the TFT array substrate110. The top electrode layer130is located on a bottom surface123of the light-transmitting substrate120. The display medium layer140is located between the top electrode layer130and the bottom electrode layer112. The barrier layer150is directly formed on at least one of a top surface121and the bottom surface123of the light-transmitting substrate120. In the specifications, “directly formed” is referred to as forming another layer along the surface of one layer so that the two layers are in contact with each other. The light-transmitting substrate120can be specially treated (such as plasma bombardment) so as to have sufficient bonding strength between it and the top electrode layer130, and thus the barrier layer150and the top electrode layer130can be integrated on the same film material. The barrier layer150and the top electrode layer130may be formed by chemical vapor deposition (CVD) and physical vapor deposition (PVD), but the present disclosure is not limited in this regard. In this embodiment, the barrier layer150is directly formed on the top surface121of the light-transmitting substrate120. Moreover, the barrier layer150is in direct contact with the light-transmitting substrate120, and can be used to resist moisture (water vapor).

In some embodiments, the material of the barrier layer150may be, but not limited to silicon oxide (SiO2). The top electrode layer130and the bottom electrode layer112are transparent electrodes, and the material of them is such as indium tin oxide (ITO), but not limited thereto. The TFT array substrate110and the light-transmitting substrate120both are flexible, and are bendable flexible substrates. The material of the TFT array substrate110and the light-transmitting substrate120may be, but not limited to polyethylene terephthalate (PET). For example, polyimide (PI) may also be used as the material of the flexible substrates. The front panel laminate (FPL) of the electronic paper display device100may include the light-transmitting substrate120, the top electrode layer130, and the display medium layer140. The top surface111of the TFT array substrate110has a TFT array electrically connected to the bottom electrode layer112. Moreover, the display medium layer140may be an electronic ink (i.e., electrophoretic ink; E-ink) layer including plural microcapsules142, and each of the microcapsules142has charged particles144and146with different colors. For example, the charged particles144are black particles, and the charged particles146are white particles, but the present disclosure is not limited to this regard. The top electrode layer130and the bottom electrode layer112can apply a voltage to the display medium layer140, such that the display medium layer140shows bright and dark changes. For example, the charged particles146are driven to upper positions to present a white color, or the charged particles144are driven to upper positions to present a black color. In another embodiment, the charged particles144and146may be other colors.

Specifically, since the top electrode layer130of the electronic paper display device100is located on the bottom surface123of the light-transmitting substrate120, and the barrier layer150is directly formed on the top surface121of the light-transmitting substrate120, the light-transmitting substrate120on which the top electrode layer130and the barrier layer150are disposed has the functions of conducting electricity and blocking water vapor (moisture), and can replace an upper substrate of a front panel laminate (FPL) and an overlying anti-moisture protective sheet (a substrate having a moisture barrier layer) of a traditional electronic paper display device, and can further omit an optical clear adhesive (OCA) used to attach the upper substrate and the protective sheet.

FIG.2is a schematic view of the electronic paper display device100ofFIG.1when being in use. The electronic paper display device100can effectively reduce the number of stack layers, and merely has three layers of main structures, that is, the TFT array substrate110, the display medium layer140, and a single light-transmitting substrate120. Such a design can reduce the height t of the water blocking zone between the top surface111of the TFT array substrate110and the barrier layer150by 20% compared with a traditional electronic paper display device. Based on the theory of water vapor penetration, the expected amount of moisture intrusion of the electronic paper display device100can be reduced by 20% to improve the reliability of the electronic paper display device100.

In addition, the electronic paper display device100can reduce the overall thickness and the material cost, which is beneficial to product competitiveness. Since a substrate having a moisture barrier layer and an optical clear adhesive used in a traditional electronic paper display device are removed, when the electronic paper display device100receives incident light L1(e.g., sunlight), the incident light L1can be reflected by the display medium layer140only after passing through the barrier layer150, the light-transmitting substrate120, and the top electrode layer130in sequence. Moreover, reflected light L2only passes through the top electrode layer130, the light-transmitting substrate120, and the barrier layer150in sequence so as to be viewed by human eyes, which can effectively improve optical transmittance and is beneficial to the user experience.

In this embodiment, the barrier layer150is directly formed on the top surface121of the light-transmitting substrate120, and the top electrode layer130is directly formed on the bottom surface123of the light-transmitting substrate120. The light-transmitting substrate120is located between the barrier layer150and the top electrode layer130. The top surface of the barrier layer150is exposed. The light-transmitting substrate120has a sidewall125adjacent to the top surface121and the bottom surface123, and the sidewall125of the light-transmitting substrate120, the edge of the barrier layer150, and the edge of the top electrode layer130are aligned with each other in a vertical direction D.

Furthermore, the edge of the display medium layer140is recessed from the sidewall125of the light-transmitting substrate120so that the light-transmitting substrate120has a protruding portion124. In other words, the size of the display medium layer140(e.g., length or width) along a horizontal direction is less than the size of the light-transmitting substrate120along the horizontal direction (e.g., length or width). As a result, the bottom surface123of the light-transmitting substrate120has a functional area126extending outward from the display medium layer140, and the top electrode layer130may extend to the functional area126. The functional area126caused by the different sizes between the light-transmitting substrate120and the display medium layer140may serve as a water blocking zone or a conductive area. For example, the functional area126may be used for being filled with waterproof glue to have water-blocking function, or filled with conductive glue to have the function of conducting electricity.

In this embodiment, the electronic paper display device100may further include a sealant160. The sealant160is located between the protruding portion124of the light-transmitting substrate120and the TFT array substrate110, and the sealant160surrounds the display medium layer140. The sealant160may be glue material for blocking moisture, such as water-blocking glue. The sealant160may be in contact with the bottom surface and the edge of the top electrode layer130for protection. The sealant160can extend to the lower portion of the sidewall125of the light-transmitting substrate120, such that the upper portion of the sidewall125of the light-transmitting substrate120is exposed. In other embodiments, the sealant160may cover the entire sidewall125of the light-transmitting substrate120as deemed necessary by design.

It is to be noted that the connection relationships, the materials, and the advantages of the elements described above will not be repeated in the following description. In the following description, other types of electronic paper display devices will be explained.

FIG.3is a cross-sectional view of an electronic paper display device100aaccording to another embodiment of the present disclosure. The electronic paper display device100aincludes the thin film transistor (TFT) array substrate110, the light-transmitting substrate120, the top electrode layer130, the display medium layer140, a barrier layer150a,and the sealant160. The differences between this embodiment and the embodiment ofFIG.1are that the barrier layer150ais directly formed on the bottom surface123of the light-transmitting substrate120, and the top surface121of the light-transmitting substrate120is exposed. Moreover, the top electrode layer130of the electronic paper display device100ais directly formed on the bottom surface of the barrier layer150a,such that the top electrode layer130is in direct contact with the barrier layer150a.The top electrode layer130is located between the barrier layer150aand the display medium layer140.

In this embodiment, the bottom surface123of the light-transmitting substrate120has the functional area126extending outward from the display medium layer140, and the barrier layer150aand the top electrode layer130extend to the functional area126. In some embodiments, the functional area126may be filled with waterproof glue to form a water blocking zone, or filled with conductive glue to form an area having the function of conducting electricity. In addition, the sealant160may be in contact with and cover the bottom surface and the edge of the top electrode layer130and the edge of the barrier layer150afor protection.

FIG.4is a cross-sectional view of an electronic paper display device100baccording to still another embodiment of the present disclosure. The electronic paper display device100bincludes the thin film transistor (TFT) array substrate110, the light-transmitting substrate120, the top electrode layer130, the display medium layer140, the barrier layers150and150a,and the sealant160. The differences between this embodiment and the embodiments ofFIGS.1and3are that the electronic paper display device100bhas the barrier layers150and150athat are directly formed on the top surface121and the bottom surface123of the light-transmitting substrate120, respectively. The barrier layer150ais directly formed on the bottom surface123of the light-transmitting substrate120, and the top electrode layer130is directly formed on the bottom surface of the barrier layer150a,such that the top electrode layer130is in direct contact with the barrier layer150a.The barrier layers150and150alocated on the top surface121and the bottom surface123of the light-transmitting substrate120can allow the electronic paper display device100bto have a better moisture-resistant capability. Since the electronic paper display device100bhas the two barrier layers150and150a,lower-cost materials for the barrier layer can be used to achieve moisture-resistant effect similar to that of the electronic paper display devices100and100a.

It is to be noted that the connection relationships, the materials, and the advantages of the elements described above will not be repeated in the following description. In the following description, the manufacturing method of the aforementioned electronic paper display device will be explained.

FIG.5is a flow chart of a manufacturing method of an electronic paper display device according to one embodiment of the present disclosure. In step S1, as shown inFIGS.1,3, and4, the barrier layer150or150amay be directly formed on at least one of the top surface121and the bottom surface123of the light-transmitting substrate120, such as the barrier layer150ofFIG.1formed on the top surface121of the light-transmitting substrate120; the barrier layer150aofFIG.3formed on the bottom surface123of the light-transmitting substrate120; and the barrier layers150and150aofFIG.4respectively formed on the top surface121and the bottom surface123of the light-transmitting substrate120. Thereafter, in step S2, the top electrode layer130may be formed on the bottom surface123of the light-transmitting substrate120. In the embodiments ofFIGS.3and4, the barrier layer150ais formed on the bottom surface123of the light-transmitting substrate120, and then the top electrode layer130is formed on the barrier layer150asuch that the barrier layer150ais located between the top electrode layer130and the bottom surface123of the light-transmitting substrate120.

In step S3, the display medium layer140may be formed on the light-transmitting substrate120, such as by coating. As a result, the light-transmitting substrate120and the display medium layer140may be regarded as the same film material. Steps S1to S3can be performed by roll-to-roll manufacturing process. Thereafter, in step S4, the light-transmitting substrate120and the display medium layer140may be disposed on the thin film transistor (TFT) array substrate110, such that the display medium layer140is located between the light-transmitting substrate120and the TFT array substrate110, and between the top electrode layer130and the bottom electrode layer112of the TFT array substrate110.

FIG.6is a cross-sectional view of an electronic paper display device100caccording to yet another embodiment of the present disclosure. The electronic paper display device100cincludes the thin film transistor (TFT) array substrate110, the light-transmitting substrate120that has the function of blocking water vapor, the top electrode layer130, the display medium layer140, and the sealant160. The edge of the display medium layer140is recessed from the sidewall125of the light-transmitting substrate120so that the light-transmitting substrate120has the protruding portion124. The sealant160is located between the protruding portion124of the light-transmitting substrate120and the TFT array substrate110, and the sealant160surrounds the display medium layer140. The difference between this embodiment and the embodiment ofFIG.1is that the electronic paper display device100chas no barrier layer150ofFIG.1. Since the material of the light-transmitting substrate120of the electronic paper display device100citself has the capability to block water and vapor, additional aforementioned barrier layers150and150aare unneeded. In other words, the electronic paper display device100aofFIG.3may omit the barrier layer150a,while the electronic paper display device100bofFIG.4may omit at least one of the barrier layers150and150a.