Display panel

A display panel has a display area and a peripheral area. The peripheral area is located outside the display area. The display panel includes a first substrate, a second substrate, and a display medium layer. The second substrate is located above the first substrate and includes a first polarization layer, a first quarter wave plate (QWP), a reflection layer, and a pixel array. The first polarization layer is located within the display area and the peripheral area and includes a wire-grid polarizer. The first QWP is located within the peripheral area. The reflection layer is located within the peripheral area, in which the first QWP is located between the first polarization layer and the reflection layer. The pixel array is at least located within the display area. The display medium layer is located between the first substrate and the second substrate.

RELATED APPLICATIONS

This application claims priority to Taiwan Application Serial Number 108112549, filed Apr. 10, 2019, which is herein incorporated by reference.

BACKGROUND

Field of Invention

The present disclosure relates to a display panel.

Description of Related Art

In various consumer electronic products, display panels have been widely utilized to provide images or operation menus. In this regard, with the development of science and technology, display panels have also developed into a variety of forms. For example, not only can mirror display panels provide images or operation menus, but they can also provide the mirror function to satisfy the demand of the consumers.

For a mirror display panel, one piece of traditional semi lens glass is required on the display panel, and the display area and the peripheral area of the display panel are able to provide specular reflection functions. However, owing to the different structures of the display area and the peripheral area of the display panel, the specular reflection effects provided by them are different, which in turn causes the user experience of the customers to be affected. That is to say, in the development of the mirror display panel, how to lighten the weight and uniform the specular reflection effect has become one of the important subjects in related fields.

SUMMARY

A display panel is provided. The display panel has a display area and a peripheral area. The peripheral area is located outside the display area. The display panel comprises a first substrate, a second substrate, and a display medium layer. The second substrate is located above the first substrate and comprises a first polarization layer, a first quarter wave plate, a reflection layer, and a pixel array. The first polarization layer is located within the display area and the peripheral area and comprises a wire-grid polarizer. The first quarter wave plate is located within the peripheral area. The reflection layer is located within the peripheral area. The first quarter wave plate is located between the first polarization layer and the reflection layer. The pixel array is at least located within the display area. The display medium layer is located between the first substrate and the second substrate.

In the foregoing, the first quarter wave plate is further located within the display area, and the second substrate further comprises a second quarter wave plate. The second quarter wave plate is located within the display area, and the second quarter wave plate and the first quarter wave plate are together located between the pixel array and the first polarization layer. The display panel further comprises a second polarization layer, and the first quarter wave plate, the second quarter wave plate, and the display medium layer are together located between the second polarization layer and the first polarization layer.

In the foregoing, an optical axis of the first quarter wave plate is positive 45 degrees relative to an optical axis of the second polarization layer, and an optical axis of the second quarter wave plate is negative 45 degrees relative to the optical axis of the second polarization layer.

In the foregoing, the second substrate further comprises a light absorption layer. The light absorption layer is located between the first polarization layer and the pixel array, and located between the first polarization layer and the first quarter wave plate.

In the foregoing, a material of the reflection layer comprises aluminum, gold, silver, titanium, molybdenum oxide, tantalum, or a combination thereof.

In the foregoing, the first substrate comprises a plurality of color resist layers, and a vertical projection range of the first substrate on the second substrate falls within a boundary of the first polarization layer.

In the foregoing, each of the first quarter wave plate and the reflection layer is in a loop and surrounds the display area.

In the foregoing, the second substrate further comprises a drive circuit layer. The drive circuit layer is located within the peripheral area and electrically connected to the pixel array, and the reflection layer is located between the drive circuit layer and the first polarization layer.

The present disclosure provides a display panel. The display panel has a display area and a peripheral area. The peripheral area is located outside the display area. The display panel comprises a first substrate and a second substrate. The first substrate comprises a light emitting diode array, and the light emitting diode array is located within the display area. The second substrate is located above the first substrate and comprises a first polarization layer, a first quarter wave plate, and a light absorption layer. The first polarization layer is located within the display area and the peripheral area, and comprises a wire-grid polarizer. The first quarter wave plate is located within the display area and the peripheral area. The light absorption layer is located within the display area and the peripheral area, and the light absorption layer and the first quarter wave plate are together located between the first substrate and the first polarization layer, and the light absorption layer is located between the first quarter wave plate and the first polarization layer.

In the foregoing, the first substrate further comprises a circuit layer. The circuit layer is at least located within the peripheral area and electrically connected to the light emitting diode array, and the light absorption layer and the first quarter wave plate are together located between the circuit layer and the first polarization layer.

With the above configuration, the display panel can be switched between the image mode and the specular reflection mode. When the display panel is in the image mode, the display medium layer can be controlled through the pixel array so that the display panel provides the image. When the display panel is in the specular reflection mode, the light beams leaving from the interior of the display panel can be attenuated by the layers in the second substrate to uniform the specular reflection effect provided by the display panel.

DESCRIPTION OF THE EMBODIMENTS

It will be understood that, although the terms first, second, third etc. may be used herein to describe various elements, components, areas, regions, layers and/or sections, these elements, components, areas, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, area, region, layer or section from another element, component, area, region, layer or section. Thus, a first element, component, area, region, layer or section discussed below could be termed a second element, component, area, region, layer or section without departing from the teachings of the present disclosure. As used herein, “about,” “approximately,” or “substantially” includes the value and average values within acceptable deviations of the particular value determined by one of ordinary skill in the art. For example, “about,” “approximately,” or “substantially” can mean within one or more standard deviations of the value, or within ±30%, ±20%, ±15%, ±10%, ±5% of the value.

A description is provided with reference toFIG. 1AandFIG. 1B.FIG. 1Ais a top schematic diagram of a display panel100A according to a first embodiment of the present disclosure.FIG. 1Bis a schematic cross-sectional view taken along line1B-1B′ inFIG. 1A. As shown inFIG. 1A, the display panel100A has a display area102and a peripheral area104, and the peripheral area104is located outside the display area102. The display panel100A can provide an image through the display area102. The peripheral area104may be regarded as a bezel of the display panel100A, which may be, for example, an area where wirings are placed. As shown inFIG. 1B, the display panel100A comprises a first substrate110, a second substrate120, and a display medium layer130. The second substrate120is located above the first substrate110, and the display medium layer130is located between the first substrate110and the second substrate120.

The first substrate110may be a color filter substrate. In greater detail, the first substrate110may comprise a first transparent substrate112and color resist layers114, and the color resist layers114are disposed on the first transparent substrate112. In some embodiments, the first transparent substrate112may be a glass substrate. In some embodiments, each of the color resist layers114may be a red color resist layer, a green color resist layer, or a blue color resist layer.

The display panel100A may further comprise a spacer106. The spacer is located between the first substrate110and the second substrate120. In greater detail, the spacer106may be disposed on the first substrate110and support the second substrate120so that the first substrate110can be spaced apart from the second substrate120by a distance. The display medium layer130fills between the first substrate110and the second substrate120, and may have a display medium132. The display medium132is, for example, liquid crystal molecules.

The second substrate120may be an integration of a polarizing structure and a pixel array. In greater detail, the second substrate120may comprise a pixel array122, a drive circuit layer124, a first isolation layer126, a reflection layer128, a second isolation layer140, a first quarter wave plate142, a light absorption layer144, a first polarization layer146, and a second transparent substrate148.

The pixel array122is at least located within the display area102. The pixel array122may comprise thin film transistors and pixel electrodes (not shown in the figure). The thin film transistors are electrically connected to the pixel electrodes to apply a voltage to the pixel electrodes through the thin film transistors so that an electric field is coupled. The electric field coupled by the pixel array122can control the display medium132of the display medium layer130to rotate the display medium132. The drive circuit layer124is located within the peripheral area104, and the drive circuit layer124can be electrically connected to the pixel array122. In some embodiments, the drive circuit layer124may comprise a gate on array (GOA), outer lead boning (OLB) contacts, a fan-out package, electrode pads, wirings, or a combination thereof. In some embodiments, the pixel array122may be electrically connected to an external circuit or a connection terminal through the drive circuit layer124.

The first isolation layer126is disposed on the pixel array122and the drive circuit layer124. In some embodiments, a material of the first isolation layer126may be an organic material or an inorganic material, such as an epoxy resin, silicon oxide (SiOx), silicon nitride (SiNx), a composite layer composed of silicon oxide and silicon nitride, or other suitable dielectric material.

The reflection layer128is disposed on the first isolation layer126, and is located within the peripheral area104. The reflection layer128can be separated from the pixel array122and the drive circuit layer124through the first isolation layer126. The reflection layer128may be in a loop. In greater detail, the reflection layer128is in the loop at a view angle perpendicular to the display panel100A (for example, the view angle inFIG. 1A) and surrounds the display area102. In other words, an inner boundary of the looped reflection layer128may be aligned with a boundary between the display area102and the peripheral area104. In addition, in the embodiment shown inFIG. 1B, the looped reflection layer128may surround part of the first isolation layer126. In some embodiments, a material of the reflection layer128may comprise aluminum, gold, silver, titanium, molybdenum oxide, tantalum, or a combination thereof. Under the circumstances that the material of the reflection layer128comprises molybdenum oxide, tantalum, or the combination thereof, the reflection layer128also has light-absorbing property in addition to light-reflecting property. For example, the combination of molybdenum oxide and tantalum can form a blackened material and have the light-absorbing property, thus resulting in a light reflectance that can be provided approximately greater than 0% and less than 10%. In some embodiments, a thickness of the reflection layer128may be between 50 nanometers (nm) and 300 nanometers.

The second isolation layer140is disposed on the first isolation layer126and the reflection layer128. In some embodiments, a material of the second isolation layer140may be an organic material or an inorganic material, such as an epoxy resin, silicon oxide (SiOx), silicon nitride (SiNx), a composite layer composed of silicon oxide and silicon nitride, or other suitable dielectric material.

The first quarter wave plate142is disposed on the second isolation layer140, and is located within the peripheral area104. The first quarter wave plate142may also be in a loop. That is, the first quarter wave plate142is in the loop at the view angle perpendicular to the display panel100A (for example, the view angle inFIG. 1A) and surrounds the display area102. Similarly, in the configuration shown inFIG. 1B, the looped first quarter wave plate142may surround part of the second isolation layer140. In some embodiments, the first quarter wave plate142may comprise a liquid crystal film, a grating structure, a nanostructure, or a combination thereof. In some embodiments, a thickness of the grating structure or the nanostructure of the first quarter wave plate142may be between 600 nanometers and 1500 nanometers. Although inFIG. 1Bthe first quarter wave plate142is depicted to be separated from the reflection layer128through the second isolation layer140, the present disclosure is not limited in this regard. In other embodiments, the reflection layer128and the first quarter wave plate142may be configured in a stack and in contact with each other.

A description is provided with reference toFIG. 1BandFIG. 1C.FIG. 1Cis an enlarged schematic diagram of a region C inFIG. 1B. The light absorption layer144and the first polarization layer146are disposed on the second isolation layer140and the first quarter wave plate142, and are located within the display area102and the peripheral area104. In the peripheral area104, the drive circuit layer124, the reflection layer128, the first quarter wave plate142, the light absorption layer144, and the first polarization layer146may be stacked in sequence. In greater detail, the first quarter wave plate142and the light absorption layer144together may be located between the first polarization layer146and the reflection layer128, and the reflection layer128is located between the drive circuit layer124and the first polarization layer146.

The first polarization layer146comprises a wire-grid polarizer (WGP). In greater detail, the wire-grid polarizer of the first polarization layer146may be formed by a plurality of parallel metal wires147. The wire-grid polarizer of the first polarization layer146can allow a light beam in a single polarization state (such as P polarization) to pass through and a light beam of another polarization state (such as S polarization) to be reflected. In some embodiments, a thickness of the first polarization layer146may be between 100 nanometers and 500 nanometers.

The light absorption layer144may be located between the pixel array122and the first polarization layer146, and is also located between the first quarter wave plate142and the first polarization layer146. In greater detail, the metal wires147of the first polarization layer146may have lower surfaces, and the lower surfaces face the first quarter wave plate142or the second isolation layer140. The light absorption layer144may be disposed on the lower surfaces of the metal wires147of the first polarization layer146. A material of the light absorption layer144can allow a light absorption rate of the light absorption layer144to be greater than 90%. In some embodiments, the material of the light absorption layer144may comprise molybdenum oxide, tantalum, or a combination thereof. As mentioned previously, the combination of molybdenum oxide and tantalum can form the blackened material. In some embodiments, a thickness of the light absorption layer144may be between 50 nanometers and 150 nanometers.

The second transparent substrate148is disposed on the pixel array122, the drive circuit layer124, the first isolation layer126, the reflection layer128, the second isolation layer140, the first quarter wave plate142, the light absorption layer144, and the first polarization layer146. The second transparent substrate148may be a glass substrate, which can be used as a carrier substrate of the second substrate120during a process. For example, a formation method of the first polarization layer146may comprise forming a metal layer on the second transparent substrate148, and then patterning the metal layer into the plurality of parallel metal wires147.

That is to say, layers from the first polarization layer146to the pixel array122are sequentially formed on the second transparent substrate148, so that the reflection layer128, the first quarter wave plate142, and the first polarization layer146may be regarded as an embedded structure of the display panel100A. As a result, the integration of the polarizing structure and the pixel array is achieved. In addition, under the circumstances that layers above the pixel array122use metallic materials, these layers can be compatible with a process temperature of the pixel array122. For example, under the circumstances that the reflection layer128is formed by using a metallic material and the first quarter wave plate142is formed by adopting an inorganic nano-grating structure, the reflection layer128and the first quarter wave plate142are prevented from being affected by the process temperature of pixel array122. In addition to that, such a configuration can allow the second substrate120to be fabricated by using a single carrier substrate, so that the lightweight display panel100A can be achieved.

Additionally, the display panel100A further comprises a backlight module150and a second polarization layer156. The backlight module150is disposed on a same side as the first substrate110and the display medium layer130, and the first substrate100is located between the backlight module150and the display medium layer130. The backlight module150comprises a frame152and a light source154. The light source154is disposed in the frame152. The light source154may comprise light emitting elements and a light guide plate (not shown in the figure), and is configured to provide illumination to the first substrate110. The second polarization layer156may be adhered to the first transparent substrate112of the first substrate110, so that the first transparent substrate112is located between the second polarization layer156and the color resist layers114. In some embodiments, a structure of the second polarization layer156is different from the first polarization layer146. For example, the second polarization layer156may be an absorbing polarizer, that is, the second polarization layer156can allow a light beam in a single polarization state (such as P polarization) to pass through and absorb a light beam in another polarization state (such as S polarization). In some embodiments, an optical axis of the first polarization layer146is orthogonal to an optical axis of the second polarization layer156, and an optical axis of the first quarter wave plate142has a phase difference of 45 degrees relative to an optical axis of the second polarization layer156.

Through the above configuration, the display panel100A can provide a full specular reflection effect. Here, “full” comprises the display area102and the peripheral area104. In greater detail, the display panel100A can be switched between an image mode and a specular reflection mode.

When the display panel100A is in the image mode, pixel electrodes can be driven correspondingly through the pixel array122for a pixel area to provide an image so as to couple the electric field. The display medium132of the display medium layer130is thus controlled. The display medium132in the display medium layer130affected by the electric field can maintain a polarization state of light beams that pass through unchanged. Then, when the backlight module150provides light beams towards the first substrate110, the second polarization layer156can allow P-polarized light to pass through. After the P-polarized light passes through the display medium layer130, a polarization state of the P-polarized light can be maintained. After that, when the P-polarized light reaches the first polarization layer146, the P-polarized light can pass through the first polarization layer146due to the P polarization state. As a result, the corresponding pixel area of the display panel100A can provide the image.

When the display panel100A is in the image mode, for a pixel area to provide a black effect, a polarization state of light beams that pass through can be changed through an optical activity of the display medium layer130. Therefore, after the second polarization layer156allows the P-polarized light to pass through, a polarization state of light beams passing through the display medium layer130from the second polarization layer156is S polarization, that is S-polarized light is generated. Then, when the S-polarized light reaches the first polarization layer146, the S-polarized light can be reflected from the first polarization layer146due to the S polarization state. In other words, light beams propagate from the first substrate110towards the second substrate120do not leave the display area102of the display panel100A, so that the corresponding pixel area of the display panel100A can provide the black effect.

When the display area102of the display panel100A is so switched that a whole pixel area provides the black effect, the display panel100A can be switched to the specular reflection mode. However, the present disclosure is not limited in this regard. In other embodiments, the display panel100A can also be switched between the image mode and the specular reflection mode by switching whether to provide the illumination of the backlight module150or not.

When the display panel100A is in the specular reflection mode, for light beams above the display panel100A propagating towards the display panel100A, S-polarized light in the light beams will be reflected from the first polarization layer146so that the display panel100A can provide the specular reflection effect through the reflected S-polarized light. In addition, P-polarized light in the light beams will pass through the first polarization layer146and enter the display panel100A. In this regard, light intensity of the P-polarized light when leaving the display panel100A can be reduced through the layer configuration in the display panel100A, thus uniforming the specular reflection effects of the display area102and the peripheral area104.

A description is provided with reference toFIG. 1D.FIG. 1Dis a schematic cross-sectional view of the display panel100A ofFIG. 1Bwhen the display panel100A is in the specular reflection mode. Optical paths of the light beams above the display panel100A propagating towards the display panel100A are further described as follows. To simplify matters, a light beam above the display panel100A propagating towards the display area102of the display panel100A is represented by a light beam L1, and light beams above the display panel100A propagating towards the peripheral area104of the display panel100A are represented by light beams L2.

When the light beam L1reaches the first polarization layer146, S-polarized light in the light beam L1is reflected from the first polarization layer146(this S-polarized light is represented by a light beam L1S). In addition to that, P-polarized light in the light beam L1can pass through the first polarization layer146, and the P-polarized light will be converted into S-polarized light after passing through the display medium layer130. After that, the S-polarized light converted by the display medium layer130is absorbed by the second polarization layer156.

When the light beam L2reaches the first polarization layer146, S-polarized light in the light beam L2is reflected from the first polarization layer146(this S-polarized light is represented by a light beam L2S). In addition to that, P-polarized light in the light beam L2can pass through the first polarization layer146, and propagates towards the first quarter wave plate142. The P-polarized light will be converted into circularly polarized light after passing through the first quarter wave plate142, and the circularly polarized light is then reflected from the reflection layer128. In this regard, after the circularly polarized light is reflected from the reflection layer128, its polarization direction is reversed, so that the circularly polarized light reflected from the reflection layer128is converted into S-polarized light after passing through the first quarter wave plate142and propagates towards the first polarization layer146. After that, this S-polarized light is reflected from the first polarization layer146, and reaches the first quarter wave plate142again. In the optical path where the S-polarized light propagates from the first quarter wave plate142to the first polarization layer146and is then reflected back to the first quarter wave plate142, the light intensity of the S-polarized light is attenuated because of the absorption of the light absorption layer144.

Even if the S-polarized light is converted into P-polarized light in the subsequent optical path and passes through the first polarization layer146(this P-polarized light is represented by light beams L2P), the light intensity of the light beam L2P is much less than the light intensity of the light beam L1S or L2S after the attenuation by the light absorption layer144. As a result, the light intensity of the light beam L1S approaches a sum of the light intensities of the light beams L2P and L2S.

Therefore, the reflectance of the display area approaches the reflectance of the peripheral area in the display panel through the above configuration. The difference between the illumination intensities provided by the display area and the peripheral area can thus be reduced when the display panel is in the specular reflection mode. In this regard, since the specular reflection effect provided by the display panel correlates with the illumination intensities that are provided, the above configuration can be used to uniform the specular reflection effects provided by the display area and the peripheral area so as to reduce the identifiability of the boundary between the display area and the peripheral area. As a result, a user's viewing experience of the specular reflection effect is improved.

Additionally, since the peripheral area104of the display panel100A does not need to provide any image, the first substrate110that serves as the color filter substrate is not required to be extended to the peripheral area104of the display panel100A. Hence, a size of the first substrate110is smaller than a size of the second substrate. Here, the size includes “length” and “width”. For example, a width W1of the first substrate110is smaller than a width W2of the second substrate120, as shown inFIG. 1B. In greater detail, a vertical projection range of the first substrate110on the second substrate120falls within a boundary of the first polarization layer146. Through this configuration, a space underneath the second substrate120in the peripheral area104of the display panel100A can be used for accommodating some other elements. For example, the bezel (not shown in the figure) of the display panel100A can be extended thereto. Alternatively, the space can be used for accommodating other circuit configurations.

In addition to that, the material of the reflection layer128may be adjusted depending on reflection requirements or process conditions. In some embodiments, the reflection layer128may be formed by using a blackened material to enhance the previously mentioned uniforming effect. In other embodiments, the reflection layer128may be formed by using a metallic material, such as aluminum, so as to meet the process conditions.

A description is provided with reference toFIG. 2A.FIG. 2Ais a schematic cross-sectional view of a display panel100B according to a second embodiment of the present disclosure. At least one difference between the present embodiment and the first embodiment is that a structure of the second substrate120according to the present embodiment is different from a structure of the second substrate120according to the first embodiment, and the second substrate120according to the present embodiment further comprises a second quarter wave plate160.

Since the configuration of the pixel array122and the drive circuit layer124of the second substrate120according to the present embodiment is similar to that of the first embodiment, a description in this regard is not provided. A third isolation layer162covers the pixel array122and the drive circuit layer124. A material of the third isolation layer162may be the same as the material of the first isolation layer126.

The reflection layer128and the second quarter wave plate160are disposed on the third isolation layer162. The reflection layer128is located within the peripheral area104, and the second quarter wave plate160is located within the display area102. Similarly, the reflection layer128is in a loop, and the looped reflection layer128may surround the second quarter wave plate160. In the embodiment shown inFIG. 2A, a material of the reflection layer128may comprise molybdenum oxide, tantalum, or a combination thereof, and the second quarter wave plate160may comprise a liquid crystal film, a grating structure, a nanostructure, or a combination thereof.

The second transparent substrate148is disposed on the pixel array122, the drive circuit layer124, the third isolation layer162, the reflection layer128, and the second quarter wave plate160, and layers from the reflection layer128and the second quarter wave plate160to the pixel array122may be sequentially formed on the second transparent substrate148. The reflection layer128and the second quarter wave plate160can thus be regarded as an embedded structure of the display panel1006.

In the present embodiment, positions of the first quarter wave plate142and the first polarization layer146are changed to be above the second transparent substrate148. That is, the first quarter wave plate142and the first polarization layer146and the pixel array122are located on opposite sides of the second transparent substrate148. The first quarter wave plate142is located between the second transparent substrate148and the first polarization layer146. Additionally, the first quarter wave plate142may further be located within the display area102, that is, both the first quarter wave plate142and the first polarization layer146are located within the display area102and the peripheral area104.

The second transparent substrate148can also be used as a carrier substrate when forming the first quarter wave plate142and the first polarization layer146. In other words, the first quarter wave plate142and the first polarization layer146are sequentially formed on the second transparent substrate148. Therefore, each layer of the second substrate120can be completed under the circumstances that a single transparent substrate is used, thus reducing the number of transparent substrates used to achieve the lightweight display panel100B. In addition, the second substrate120may further comprise a fourth isolation layer164disposed on the first polarization layer146. A material of the fourth isolation layer164may be the same as the material of the above first isolation layer126, and the fourth isolation layer164is used as a protective layer to make the second substrate120scratch-resistant, abrasion-resistant, and moisture-resistant.

The first quarter wave plate142and the second quarter wave plate160of the second substrate120, the display medium layer130, the first polarization layer146, and the second polarization layer156may be in a stacked relationship. For example, the second quarter wave plate160and the first quarter wave plate142are together located between the pixel array122and the first polarization layer146, and the second quarter wave plate160, the first quarter wave plate142, and the display medium layer130are together located between the second polarization layer156and the first polarization layer146.

The first quarter wave plate142may comprise a liquid crystal film, a grating structure, a nanostructure, or a combination thereof. A size of the first quarter wave plate142is larger than a size of the second quarter wave plate160. Here, the size includes “area”, “length” and “width”. For example, a width W3of first quarter wave plate142is greater than a width W4of second quarter wave plate160, as shown inFIG. 2A. Additionally, the optical axis of the first quarter wave plate142is positive 45 degrees relative to the optical axis of the second polarization layer156, and an optical axis of the second quarter wave plate160is negative 45 degrees relative to the optical axis of the second polarization layer156.

The first polarization layer146comprises a wire-grid polarizer, and a formation method of the first polarization layer146comprises patterning a metal layer into a plurality of parallel metal wires too. In addition to that, a size of the first substrate110may also be smaller than a size of the second substrate120according to the present embodiment, so that a space underneath the second substrate120can be used for accommodating some other elements.

Through the above configuration, the display panel100B can provide a full specular reflection effect, and the display panel100B can be switched between an image mode and a specular reflection mode.

When the display panel100B is in the image mode, pixel electrodes can be driven correspondingly through the pixel array122for a pixel area to provide an image so as to couple an electric field. The display medium layer130is thus controlled to maintain a polarization state of light beams passing through the display medium layer130unchanged. Then, when the backlight module150provides light beams towards the first substrate110, the second polarization layer156can allow P-polarized light to pass through. After the P-polarized light passes through the display medium layer130, a polarization state of the P-polarized light can be maintained. Since the optical axis of the second quarter wave plate160and the optical axis of the first quarter wave plate142are negative 45 degrees and positive 45 degrees respectively relative to the optical axis of the second polarization layer156, the P-polarized light that passes through the display medium layer130still maintains P polarization state after sequentially passing through the second quarter wave plate160and the first quarter wave plate142. After that, when this P-polarized light reaches the first polarization layer146, the P-polarized light can pass through the first polarization layer146due to the P polarization state. As a result, the corresponding pixel area of the display panel1006can provide the image.

When the display panel100B is in the image mode, for a pixel area to provide a black effect, a polarization state of light beams that pass through can be changed through an optical activity of the display medium layer130. Therefore, after the second polarization layer156allows the P-polarized light to pass through, a polarization state of light beams passing through the display medium layer130from the second polarization layer156is S polarization, that is, S-polarized light is generated. The S-polarized light still maintains S polarization state after sequentially passing through the second quarter wave plate160and the first quarter wave plate142. Then, when this S-polarized light reaches the first polarization layer146, the S-polarized light can be reflected from the first polarization layer146due to the S polarization state. In other words, light beams propagate from the first substrate110towards the second substrate120do not leave the display area102of the display panel1006, so that the corresponding pixel area of the display panel100B can provide the black effect.

Similarly, when the display area102of the display panel100B is so switched that a whole pixel area provides the black effect, the display panel1006can be switched to the specular reflection mode. When the display panel100B is in the specular reflection mode, for light beams above the display panel100B propagating towards the display panel100B, S-polarized light in the light beams will be reflected from the first polarization layer146so that the display panel100B can provide the specular reflection effect through the reflected S-polarized light.

A description is provided with reference toFIG. 2B.FIG. 2Bis a schematic cross-sectional view of the display panel100B ofFIG. 2Awhen the display panel100B is in the specular reflection mode. Optical paths of the light beams above the display panel100B propagating towards the display panel100B are further described as follows. To simplify matters, a light beam above the display panel100B propagating towards the display area102of the display panel100B is represented by a light beam L1, and light beams above the display panel100B propagating towards the peripheral area104of the display panel100B are represented by light beams L2.

When the light beam L1reaches the first polarization layer146, S-polarized light in the light beam L1is reflected from the first polarization layer146(this S-polarized light is represented by a light beam L1S). P-polarized light in the light beam L1can pass through the first polarization layer146, and the P-polarized light still maintains P polarization state after sequentially passing through the second quarter wave plate160and the first quarter wave plate142. Then, the P-polarized light is converted into S-polarized light after passing through the display medium layer130, and is absorbed by the second polarization layer156afterwards.

When the light beam L2reaches the first polarization layer146, S-polarized light in the light beam L2is reflected from the first polarization layer146(this S-polarized light is represented by a light beam L2S). P-polarized light in the light beam L2can pass through the first polarization layer146, and propagates towards the first quarter wave plate142. The P-polarized light will be converted into circularly polarized light after passing through the first quarter wave plate142, and the circularly polarized light is then reflected from the reflection layer128. Since in the embodiment shown inFIG. 2B, the material of the reflection layer128comprises molybdenum oxide, tantalum, or the combination thereof, the circularly polarized light from the reflection layer128is absorbed by the reflective layer128, thus causing the light intensity to be attenuated (referred to as the first attenuation). The circularly polarized light reflected from the reflection layer128can be converted into S-polarized light after passing through the first quarter wave plate142and propagates towards the first polarization layer146. After that, this S-polarized light is reflected from the first polarization layer146, and is returned to the first polarization layer146again through repeating the above path. In the optical path where the S-polarized light is reflected from the first polarization layer146and is reflected back to the first polarization layer146again through the reflection layer128, the S-polarized light is absorbed by the reflection layer128to cause its light intensity to be attenuated by the reflection layer128(referred to as the second attenuation).

Even if the S-polarized light is converted into P-polarized light in the subsequent optical path and passes through the first polarization layer146(this P-polarized light is represented by light beams L2P), the light intensity of the light beam L2P is much less than the light intensity of the light beam L1S or L2S after two attenuations by the reflection layer128. As a result, the light intensity of the light beam L1S approaches a sum of the light intensities of the light beams L2P and L2S to uniform the specular reflection effects provided by the display area102and the peripheral area104.

A description is provided with reference toFIG. 3.FIG. 3is a schematic cross-sectional view of a display panel100C according to a third embodiment of the present disclosure. At least one difference between the present embodiment and the second embodiment is that the second substrate120according to the present embodiment further comprises the light absorption layer144. The light absorption layer144is disposed between the first quarter wave plate142and the first polarization layer146, and a material of the light absorption layer144may comprise a blackened material.

Through disposing the light absorption layer144, when P-polarized light above the display panel100C propagating towards the display panel100C enters the display panel100C, not only is the light intensity of the P-polarized light attenuated by the reflection layer128, but it is also attenuated by the light absorption layer144. In this regard, the P-polarized light is at least twice attenuated by the reflection layer128and once attenuated by the light absorption layer144. Therefore, even if the P-polarized light leaves from the peripheral area104of the display panel100C in the subsequent optical path, the light intensity of the P-polarized light is attenuated to be much less than the light intensity of light beams used for providing specular reflection to further uniform the specular reflection effects provided by the display area102and the peripheral area104.

In addition, in the embodiment shown inFIG. 3, the light absorption layer144is so disposed that it extends to the display area102. Portions of the light absorption layer144located within the display area102can prevent unexpected situations from occurring when the display area102provides the specular reflection effect. For example, when the display panel100C is in a specular reflection mode, there may be light beam(s) that are converted into P-polarized light due to multiple reflections within the display area102of the display panel100C, and thus pass through the first polarization layer146. However, the situation in which the specular reflection effects provided by the display area102and the peripheral area104are not uniform can be avoided because this P-polarized light is attenuated by the light absorption layer144in its optical path.

Although in the embodiment shown inFIG. 3the light absorption layer144is extended to the display area102, the present disclosure is not limited in this regard. In other embodiments, the light absorption layer144may not be extended to the display area102. In other words, the light absorption layer144may surround the display area102.

A description is provided with reference toFIG. 4.FIG. 4is a schematic cross-sectional view of a display panel100D according to a fourth embodiment of the present disclosure. At least one difference between the present embodiment and the first embodiment is that the display panel100D according to the present embodiment displays an image through a light-emitting diode (LED) array.

In greater detail, the display panel100D has the display area102and the peripheral area104, and the peripheral area104is located outside the display area102. The display panel100D comprises the first substrate110, the second substrate120, and a support168. The second substrate120is located above the first substrate110, and the support168is located between the first substrate110and the second substrate120. The support168may be disposed on the first substrate110and support the second substrate120so that the first substrate110can be spaced apart from the second substrate120by a distance.

The first substrate110comprises the first transparent substrate112, an LED array116, and a circuit layer119. The LED array116is disposed on the first transparent substrate112and is located within the display area102. The LED array116comprises a plurality of LEDs118, and different LEDs118can provide lights of different colors. In some embodiments, a material of the LED118comprises an organic light emitting material, and the different LEDs118may comprise different organic light emitting materials to provide light of different colors. The circuit layer119may be disposed between the first transparent substrate112and the LED array116, and is located within the display area102and the peripheral area104. The circuit layer119may be electrically connected to the LEDs118of the LED array116. In some embodiments, the circuit layer119comprises a thin film transistor array, which can be used for driving the LEDs118correspondingly.

The second substrate120comprises the second transparent substrate148, the first quarter wave plate142, the light absorption layer144, and the first polarization layer146located within the display area102and the peripheral area104. The first polarization layer146is disposed on the second transparent substrate148, and comprises a wire-grid polarizer. The first quarter wave plate142and the light absorption layer144are together located between the first substrate110and the first polarization layer146, and the light absorption layer144is located between the first quarter wave plate142and the first polarization layer146. In greater detail, the first quarter wave plate142, the light absorption layer144, and the first polarization layer146may be sequentially formed on the second transparent substrate148. Additionally, the first quarter wave plate142and the light absorption layer144are also together located between the circuit layer119and the first polarization layer146. In addition to that, the second substrate120may further comprise a fifth isolation layer166disposed on the first polarization layer146. A material of the fifth isolation layer166may be the same as the material of the first isolation layer126as mentioned previously, and the fifth isolation layer166is used as a protective layer to make the second substrate120scratch-resistant, abrasion-resistant, and moisture-resistant.

Through the above configuration, the display panel100D can provide a full specular reflection effect, and the display panel100D can be switched between an image mode and a specular reflection mode.

When the display panel100D is in the image mode, a bias voltage can be applied to the LEDs118correspondingly through the circuit layer119for a pixel area to provide an image so that the corresponding LEDs118emit light beams. After the light beams provided by the LEDs118pass through the first quarter wave plate142, portions of the light beams having a P polarization state can pass through the first polarization layer146, so that the corresponding pixel area of the display panel100D can provide the image.

When the display panel100D is in the image mode, for a pixel area to provide a black effect, the bias voltage can be removed from corresponding LEDs118so that the corresponding pixel area of the display panel100D can provide the black effect. Similarly, when the display area102of the display panel100D is so switched that a whole pixel area provides the black effect, the display panel100D can be switched to the specular reflection mode.

When the display panel100D is in the specular reflection mode, for light beams above the display panel100D propagating towards the display panel100D, S-polarized light in the light beams will be reflected from the first polarization layer146so that the display panel100D can provide the specular reflection effect through the reflected S-polarized light (represented by a light beam L3S).

In addition, P-polarized light in the light beams will pass through the first polarization layer146. Here, the P-polarized light is reflected multiple times in the display panel100D and passes through the first polarization layer146, and the light intensity of the P-polarized light is at least once attenuated by the light absorption layer144in the optical path where the P-polarized light leaves from the display panel100D. In this regard, when the display panel100D is in the specular reflection mode, the light intensity of a light beam (represented by a light beam L3P) that passes through the first polarization layer146and is to leave from the display panel100D is much less than the light intensity of the light beam L3S. As a result, the nonuniformity of the total reflected beams caused by the light beam L3P can be alleviated. In other words, the specular reflection effect provided by the display panel100D can be uniformed through the above configuration.

Additionally, according to the present embodiment, a thickness of the first quarter wave plate142may be between 600 nanometers and 1500 nanometers, a thickness of the light absorption layer144may be between 50 nanometers and 300 nanometers, and a thickness of the first polarization layer146may be between 100 nanometers and 500 nanometers. Under the circumstances that the structure used for uniforming the specular reflection effect is achieved by the first quarter wave plate142, the light absorption layer144, and the first polarization layer146, the above layer thickness ranges can be beneficial for thinning the display panel100D.

In summary, the second substrate of the display panel according to the present disclosure comprises the first polarization layer, the first quarter wave plate, the reflection layer, and the pixel array. The first polarization layer comprises the wire-grid polarizer, and the first quarter wave plate is located between the first polarization layer and the reflection layer. With the above configuration, the display panel can be switched between the image mode and the specular reflection mode. When the display panel is in the image mode, the corresponding pixel electrodes can be driven through the pixel array so that the display panel provides the image. When the display panel is in the specular reflection mode, the light beams leaving from the interior of the display panel can be attenuated by the layers in the second substrate to uniform the specular reflection effect provided by the display panel.