Patent ID: 12249617

DETAILED DESCRIPTION

In the following description of examples or aspects of the present disclosure, reference will be made to the accompanying drawings in which it is shown by way of illustration specific examples or aspects that can be implemented, and in which the same reference numerals and signs can be used to designate the same or like components even when they are shown in different accompanying drawings from one another. Further, in the following description of examples or aspects of the present disclosure, detailed descriptions of well-known functions and components incorporated herein will be omitted when it is determined that the description may make the subject matter in some aspects of the present disclosure rather unclear. The terms such as “including”, “having”, “containing”, “constituting” “make up of”, and “formed of” used herein are generally intended to allow other components to be added unless the terms are used with the term “only”. As used herein, singular forms are intended to include plural forms unless the context clearly indicates otherwise.

Terms, such as “first”, “second”, “A”, “B”, “(A)”, or “(B)” may be used herein to describe elements of the present disclosure. Each of these terms is not used to define essence, order, sequence, or number of elements, etc., but is used merely to distinguish the corresponding element from other elements.

When it is mentioned that a first element “is connected or coupled to”, “contacts or overlaps”, etc. a second element, it should be interpreted that, not only can the first element “be directly connected or coupled to” or “directly contact or overlap” the second element, but a third element can also be “interposed” between the first and second elements, or the first and second elements can “be connected or coupled to”, “contact or overlap”, etc. each other via a fourth element. Here, the second element may be included in at least one of two or more elements that “are connected or coupled to”, “contact or overlap”, etc. each other.

When time relative terms, such as “after”, “subsequent to”, “next”, “before”, and the like, are used to describe processes or operations of elements or configurations, or flows or steps in operating, processing, and manufacturing methods, these terms may be used to describe non-consecutive or non-sequential processes or operations unless the term “directly” or “immediately” is used together.

In addition, when any dimensions, relative sizes, etc. are mentioned, it should be considered that numerical values for an elements or features, or corresponding information (e.g., level, range, etc.) include a tolerance or error range that may be caused by various factors (e.g., process factors, internal or external impact, noise, etc.) even when a relevant description is not specified. Further, the term “may” fully encompasses all the meanings of the term “can”.

FIG.1is a diagram illustrating the structure of an aspect of a display device according to the present disclosure.

Referring toFIG.1, a display device10according to aspects of the present disclosure may include: a display panel100including an active area A/A and a non-active area N/A; and a control unit for driving the display panel100, such as a gate driver circuit GDC, a data driver circuit DDC, and a controller CTR.

In the display panel100, a plurality of gate lines GL and a plurality of data lines DL may be provided, and a plurality of subpixels SP may be disposed in areas in which the gate lines GL intersect the data lines DL. In addition, the display panel100may be a liquid crystal panel. The liquid crystal panel may include pixel electrodes, a common electrode, and a liquid crystal layer disposed between the pixel electrodes and the common electrode. The liquid crystal layer may display an image by changing the molecular alignments of liquid crystals in response to voltages applied to the pixel electrodes and the common electrode so as to block light or allow light to pass therethrough.

The gate driver circuit GDC is controlled by the controller CTR. The gate driver circuit GDC may control the driving timing of the plurality of subpixels SP by sequentially outputting scan signals to the plurality of gate lines GL disposed in the display panel100.

The data driver circuit DDC may receive image data from the controller CTR and convert the image data into an analog data voltage. The data driver circuit DDC may output the data voltage to the data lines DL at points in time at which a scan signal is applied through the gate lines GL so that each of the subpixels SP expresses brightness according to the image data.

The controller CTR may control the operation of the gate driver circuit GDC and the data driver circuit DDC by supplying a variety of control signals to the gate driver circuit GDC and the data driver circuit DDC.

The display device10may further include a power management integrated circuit (IC) supplying a variety of voltages or currents to the display panel100, the gate driver circuit GDC, the data driver circuit DDC, and the like or controlling a variety of voltages or currents to be supplied.

The display device10according to aspects of the present disclosure may be an organic light-emitting display device, an LCD device, a plasma display device, or the like.

When the display device10according to aspects is an OLED display device, each of the subpixels SP arranged in the display panel100may include a light-emitting diode (OLED) serving as a self-luminous device and a circuit component, such as a driver transistor, for driving the OLED.

The type and number of circuit components of each of the subpixels may be determined variously depending on functions that can be provided, the design, or the like.

FIG.2is a schematic view illustrating the cross-sectional shape of the display panel according to aspects of the present disclosure.

Referring toFIG.2, the display panel100includes a substrate110, a first reflector120, a planarization layer130, a first transparent electrode140, an emissive layer150, a second transparent layer160, a wavelength conversion layer170, and a second reflector180.

In the substrate110, a first subpixel111, a second subpixel112, and a third subpixel113are defined. The first subpixel111expresses a first color, the second subpixel112expresses a second color, and the third subpixel113expresses a third color. Each subpixel expressing a specific color may mean that the display panel emits light having a specific color in a specific subpixel area of the active area.

Circuit components for driving the subpixels of the display panel, as described above with reference toFIG.1, may be located on the substrate110. For example, the substrate110may be a thin-film transistor (TFT) substrate.

The first reflector120is located on the substrate110. In addition, the first reflector120has a hole corresponding to the first subpixel111. The first reflector120having the hole corresponding to the first subpixel111may mean that the hole is provided on a path along which light emitted from the emissive layer150located in the first subpixel111travels so that the light emitted from the emissive layer150located in the first subpixel111does not pass through the first reflector120.

The first reflector120reflects light having the first color while allowing light having the second color and light having the third color to pass therethrough. The expression the “specific light having a specific color” used herein means that the specific light has a wavelength by which the specific light may be recognized as having a specific color. Since the first reflector120reflects light having a specific color and allows light having another color to pass therethrough, the first reflector120is characterized by only reflecting light having a specific wavelength and allowing light having the other wavelengths to pass therethrough. Since the first reflector120has this characteristic, even in the case that the wavelength conversion layer170has low light conversion efficiency, light having the first color, not converted in the wavelength conversion layer170, may be redirected to the wavelength conversion layer170so as to be reused, thereby improving the luminance of the display panel100.

The first reflector120may be a distributed Bragg reflector (DBR). The DBR may include refractive index layer pairs123each comprised of a low refractive index layer121and a high refractive index layer122. That is, the DBR may have a structure in which the low refractive index layers121and the high refractive index layers122are stacked on each other in an alternating manner.

The DBR may include 10 to 20 refractive index layer pairs123each comprised of a low refractive index layer and a high refractive index layer. When the number of the refractive index layer pairs of the DBR meets this range, the DBR may effectively reflect light having the first color while effectively allowing light having the second color and light having the third color to pass therethrough, thereby improving the luminance of the display panel and reducing time and cost for a display panel fabrication process.

In the DBR, the ratio L:H of the thickness L of the low refractive index layers121with respect to the thickness H of the high refractive index layers122may be substantially 2:1. When the ratio of the thickness of the low refractive index layers121with respect to the thickness of the high refractive index layers122meets this ratio, the DBR may effectively reflect light having the first color while effectively allowing light having the second color and light having the third color to pass therethrough.

The planarization layer130is located on the substrate110. In addition, the planarization layer130occupies the hole corresponding to the first subpixel111of the first reflector120. As the planarization layer130occupies the hole of the first reflector120, one surface of the substrate110on which the first reflector120is provided may be planarized.

Differently from that illustrated inFIG.2, the planarization layer130may also be located on the first reflector120while occupying the hole corresponding to the first subpixel111of the first reflector120.

The first transparent electrode140is located on the first reflector120and also on the planarization layer130. Differently from that illustrated inFIG.2, the first transparent electrode140may be provided in a pattern corresponding to the areas of the subpixels111,112, and113, instead of being provided on the entirety of one surface of the substrate110. For example, a circuit component, such as a driver transistor for driving a light-emitting device, may be located in each of the subpixels of the substrate110, and the first transparent electrode140may be electrically connected to the driver transistor.

A material of the first transparent electrode140is not limited to a specific type as long as the material has a visible light transmittance of 80% or more at 550 nm, a surface resistance of 1000 Ω/sq or less, and a conductivity of 1000 S/m or more. For example, the first transparent electrode140may contain at least one from among indium tin oxide (ITO), graphene, Pedot:pss, silver nanowire, and carbon nanotube (CNT).

The emissive layer150is located on the first transparent electrode140. In addition, the emissive layer150emits light having the first color from the first subpixel111, the second subpixel112, and the third subpixel113.

The emissive layer150is a component of, for example, the light-emitting device located on the substrate110. The emissive layer150may be an organic layer of an organic light-emitting diode (OLED).

A bank layer114may be located on the first transparent electrode140. The bank layer114may be a pixel defining layer located to correspond to the first subpixel111, the second subpixel112, and the third subpixel113.

The second transparent layer160is located on the emissive layer150. Details of the material of the second transparent layer160are the same as those of the material of the first transparent electrode140described above. The second transparent layer160may be provided, for example, on the entirety of one surface of the substrate110.

The wavelength conversion layer170is located on the second transparent layer160. In addition, the wavelength conversion layer170in the second subpixel112converts light having the first color to light having the second color, whereas the wavelength conversion layer170in the third subpixel113converts light having the first color to light having the third color.

The wavelength conversion layer170may include a first quantum dot in the second subpixel112and a second quantum dot in the third subpixel113. For example, the wavelength conversion layer170may include an overcoat layer as a transparent organic layer, include the first quantum dot in the overcoat layer in the second subpixel112, and include the second quantum dot in the overcoat layer in the third subpixel113. The wavelength conversion layer170may only include a transparent overcoat layer190in the first subpixel111or include a pigment having the first color in the overcoat layer190.

The wavelength conversion layer170may include the first quantum dot emitting light having the second color when irradiated with light having the first color from the emissive layer150in the second subpixel112expressing the second color and the second quantum dot emitting light having the third color when irradiated with light having the first color from the emissive layer150in the third subpixel113expressing the third color.

The types of the quantum dots included in the wavelength conversion layer are not specifically limited. The wavelength conversion layer may include a monolayer quantum dot including at least one of a nanocrystal of group III-V semiconductor and a nanocrystal of group II-VI semiconductor or a multilayer quantum dot including a core/shell structure.

The quantum dot is a nanoparticle having a photoluminescence (PL) characteristic in which an electron excited to a higher energy level by external light emits light while returning to a lower energy level. This characteristic of the quantum dot may be used to convert the wavelength of light emitted from a light source of a display device. In particular, the quantum dot is characterized by emitting light having different wavelengths depending on the diameter. Thus, it is possible to advantageously use the quantum dot in the fabrication of a display device having high color purity by precisely controlling the size of the quantum dot during the fabrication thereof. Although the quantum dot has a problem of low conversion efficiency in PL emission, aspects of the present disclosure can overcome this problem.

A black matrix115may be located on the second transparent layer160. The black matrix115may be located to correspond to the first subpixel111, the second subpixel112, and the third subpixel113. The black matrix115may be located at boundaries of the subpixels so as to prevent color mixing from occurring between the subpixels.

The second reflector180is located on the wavelength conversion layer170.

The second reflector180may be, for example, an encapsulation layer encapsulating circuit components provided on the substrate110. The type of the second reflector180is not specifically limited as long as the second reflector can reflect light having the first color, light having the second color, and light having the third color while being able to protect the circuit components from external oxygen and moisture. For example, the second reflector180may be implemented as a metal layer made from aluminum (Al) or the like.

The first color may be blue, the second color may be green, and the third color may be red. In this example, the display panel100may be configured such that blue light is emitted from the emissive layer150, the first subpixel111is a subpixel expressing blue, the second subpixel112is a subpixel expressing green, due to blue light being converted into green light in the wavelength conversion layer170, and the third subpixel113is a subpixel expressing red, due to blue light being converted into red light in the wavelength conversion layer170.

FIG.3is a schematic view illustrating the cross-sectional shape of the display panel according to aspects of the present disclosure.FIG.3is intended to illustrate a path along which light emitted from the emissive layer150travels.

Referring toFIG.3, in the display panel100according to aspects of the present disclosure, the substrate110may be a viewer-side substrate. Thus, light emitted from the emissive layer150may pass through the substrate110to display an image.

Since both the first electrode140and the second electrode160, i.e., two electrodes of the light-emitting device, are transparent electrodes, a portion L1of light emitted from the emissive layer150in the first subpixel111may exit the display panel100through the substrate110, whereas another portion L2of the light emitted from the emissive layer150of the first subpixel111may travel to the reflector180, be reflected from the reflector180, and then exit the display panel100through the substrate110.

A portion L3of light having the first color emitted from the emissive layer150in the second subpixel112may exit the display panel100through a reflection step in which the light portion L3having the first color emitted from the emissive layer150in the second subpixel112strikes and is reflected from the first reflector120, a wavelength conversion step in which the light portion having the first color reflected from the first reflector120is converted into light having the second color while traveling through the wavelength conversion layer170, striking and being reflected from the second reflector, and being directed to the first reflector, and an extraction step in which the light converted in the wavelength conversion step exits the display panel100by passing through the first reflector120and the substrate110.

Since the display panel100includes the first transparent electrode140and the second transparent layer160, i.e., the two transparent electrodes, and the first reflector120and the second reflector180, i.e., the two reflectors, light, such as the light portion L3, which is not directed to the wavelength conversion layer170, may also be converted in the wavelength conversion layer170. Consequently, the display panel100may have high luminance.

Although not shown inFIG.3, another portion of the light emitted from the emissive layer150may directly travel to the wavelength conversion layer170depending on the light travel path so as to exit the display panel100through the wavelength conversion step and the extraction step without the reflection step.

Although not shown inFIG.3, a light portion not converted into light having the second color in the wavelength conversion step may strike and be reflected from the first reflector120to reenter the wavelength conversion layer170, thereby being subjected again to the wavelength conversion step.

A portion L4of light emitted from the emissive layer150in the third subpixel113may also exit the display panel100after having been converted into light having the third color through the reflection step, the wavelength conversion step, and the extraction step, in the same manner as the light portion L3emitted from the emissive layer150in the second subpixel112. In addition, a light portion not converted into light having the third color in the wavelength conversion step may also reenter the wavelength conversion layer170so as to be subjected again to the wavelength conversion step.

As described above, the display panel100according to aspects of the present disclosure includes the first transparent electrode140and the second transparent layer160, i.e., the two transparent electrodes, and the first reflector120and the second reflector180, i.e., the two reflectors. Since the first reflector120selectively reflects light having a specific color, the wavelength conversion layer170enables non-converted light to be reused. Accordingly, the display panel100may have high luminance.

FIGS.4to11are views illustrating a method of fabricating the display panel according to aspects of the present disclosure.

In the display panel100according to aspects of the present disclosure, the wavelength conversion layer may be formed after circuit components are formatted on the substrate, thereby preventing the quantum efficiency of quantum dots from being reduced due to, for example, high temperature deformation.

Referring toFIG.4, the first reflector120is formed on the substrate110. The first reflector120may be formed by, for example, chemical vapor deposition (CVD).

Referring toFIG.5, the first reflector120may be patterned by etching using a photoresist116formed on the first reflector120. Due to the patterning, the first reflector120may have a hole.

FIG.6illustrates the planarization layer130occupying the hole of the first reflector120.FIG.17illustrates the first transparent electrode140formed after the planarization and the bank layer114formed on the first transparent electrode140.

FIG.8illustrates the emissive layer150formed on the first transparent electrode140and the second transparent layer160formed on the emissive layer150.FIG.9illustrates the black matrix115formed on the second transparent layer160.

FIG.10illustrates the wavelength conversion layer170and190by, for example, inkjet printing after the black matrix115is formed. For example, the wavelength conversion layer170may include a quantum dot. Afterwards, as illustrated inFIG.11, the second reflector180may be formed, thereby fabricating the display panel according to aspects of the present disclosure.

As illustrated inFIGS.4to11, in the display panel according to aspects of the present disclosure, the wavelength conversion layer170including the quantum dots deformable at high temperature is formed after the fabrication of the circuit components performed at relatively high temperature. Accordingly, it is possible to prevent the performance of the wavelength conversion layer170from being degraded during the fabrication of the wavelength conversion layer170.

In another aspect, aspects of the present disclosure may provide a display device including the display panel and a controller driving the display panel.

The display device may include the display panel and the controller controlling the display panel.

In the display device according to aspects of the present disclosure, details of the display panel are the same as those of the display panel according to aspects of the present disclosure described above. Thus, a description of the display panel included in the display device according to aspects of the present disclosure will be omitted.

In the display device according to aspects of the present disclosure, details of the controller driving the display panel are the same as those described above, and thus, a description thereof will be omitted.

The above description has been presented to enable any person skilled in the art to make and use the technical idea of the present disclosure, and has been provided in the context of a particular application and its requirements. Various modifications, additions and substitutions to the described aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects and applications without departing from the spirit and scope of the present disclosure. The above description and the accompanying drawings provide an example of the technical idea of the present disclosure for illustrative purposes only. That is, the disclosed aspects are intended to illustrate the scope of the technical idea of the present disclosure. Thus, the scope of the present disclosure is not limited to the aspects shown, but is to be accorded the widest scope consistent with the claims. The scope of protection of the present disclosure should be construed based on the following claims, and all technical ideas within the scope of equivalents thereof should be construed as being included within the scope of the present disclosure.