Organic light emitting display device

An organic light-emitting display device includes a first substrate having sub-pixel areas, each sub-pixel area having a light-emitting area and a non-light-emitting area; thin-film transistors respectively in non-light-emitting areas of the sub-pixel areas; a first planarization layer in the sub-pixel areas while covering the thin-film transistors; organic light-emitting elements on the first planarization layer and in light-emitting areas of the sub-pixel areas; a liquid crystal layer on the organic light-emitting elements and in the sub-pixel areas and in an area between the sub-pixel areas; and a second substrate on the liquid crystal layer. Liquid crystal molecules of the liquid crystal layer in the light-emitting areas are in a hybrid alignment. In the hybrid alignment, an alignment of the liquid crystal molecules gradually changes from a horizontal alignment to a vertical alignment. Liquid crystal molecules of the liquid crystal layer in the non-light-emitting areas are in a tilted alignment.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims a benefit under 35 U.S.C. § 119(a) of Korean Patent Application No. 10-2020-0188786 filed on Dec. 31, 2020, on the Korean Intellectual Property Office, the entirety of disclosure of which is incorporated herein by reference for all purposes.

BACKGROUND

Technical Field

The present disclosure relates to an organic light-emitting display device, and more specifically, to an organic light-emitting display device capable of preventing color mixing and preventing external light reflection.

Discussion of the Related Art

As the information society develops, the demand for display devices is increasing in various forms. In response to this demand, display devices to which various display panels such as liquid crystal display panels, plasma display panels, and organic light-emitting display panels are applied are being researched and commercialized.

An organic light-emitting display device to which the organic light-emitting display panel is applied is a self-luminous display device. Unlike a liquid crystal display device, the organic light-emitting display device does not require a separate light source and thus is relatively light and thin. Further, the organic light-emitting display device operates at a low voltage, and has excellent characteristics in color rendering, response speed, viewing angle, contrast ratio, etc., and has been widely used in recent years.

However, as the organic light-emitting display device increases in size or resolution, sagging of a substrate and a fine metal mask occurs, so that it is difficult to form red, green, and blue organic light-emitting layers using the fine metal mask.

As a method to replace such method of forming the red, green, blue organic light-emitting layers using the fine metal mask, a structure in which white organic light-emitting layer is formed equally in all sub-pixels, and different color filters are employed for the sub-pixels has been proposed.

SUMMARY

An organic light-emitting display device has problems of color mixing resulted from light leakage defects between sub-pixel areas, and reflection of external light resulted from an increase in use of mobile devices.

Accordingly, embodiments of the present disclosure are directed to an organic light-emitting display device that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.

An aspect of the present disclosure is to provide an organic light-emitting display device that has excellent color purity and color gamut by ameliorating light leakage defects between adjacent sub-pixel areas, and by preventing color mixing between the adjacent sub-pixel areas.

Another aspect of the present disclosure is to provide an organic light-emitting display device capable of preventing the reflection of the external light.

According to one embodiment of the present disclosure, an organic light-emitting display device that may prevent color mixing between sub-pixel areas and ameliorate reflection of external light may be provided.

To achieve these and other aspects of the inventive concepts, as embodied and broadly described herein, an organic light-emitting display device comprises a first substrate having sub-pixel areas, wherein each sub-pixel area includes light-emitting area and non-light-emitting area, thin-film transistors respectively disposed in non-light-emitting areas of the respective sub-pixel areas, a first planarization layer disposed in the sub-pixel areas while covering the thin-film transistors, organic light-emitting elements disposed on the first planarization layer and disposed in light-emitting areas of the sub-pixel areas, a liquid crystal layer disposed on the organic light-emitting elements and disposed in the sub-pixel areas and an area between the sub-pixel areas, and a second substrate disposed on the liquid crystal layer. In this connection, liquid crystal molecules of the liquid crystal layer disposed in the light-emitting areas are in a hybrid alignment. In the hybrid alignment, an alignment of the liquid crystal molecules gradually changes from a horizontal alignment to a vertical alignment. In addition, liquid crystal molecules of the liquid crystal layer disposed in the non-light-emitting areas are in a tilted alignment.

In another aspect, an organic light-emitting display device comprises a first substrate including light-emitting portions and non-light-emitting portions, thin-film transistors disposed in each non-light-emitting portion, a first planarization layer disposed on the first substrate while covering the thin-film transistors, organic light-emitting elements disposed on the first planarization layer and disposed in the light-emitting portions, wherein the organic light-emitting elements emit white light linearly polarized in a first direction, a liquid crystal layer disposed on the organic light-emitting elements and disposed in the light-emitting portions and the non-light-emitting portions, and a second substrate disposed on the liquid crystal layer. Liquid crystal molecules of the liquid crystal layer disposed in the light-emitting portion are in a hybrid alignment. In the hybrid alignment, an alignment of the liquid crystal molecules gradually changes from a horizontal alignment to a vertical alignment. In addition, liquid crystal molecules of the liquid crystal layer disposed in the non-light-emitting portion are in a tilted alignment.

According to the present disclosure, the liquid crystal molecules of the liquid crystal layer disposed in the light-emitting portion equipped with the organic light-emitting elements and the like are in a hybrid alignment in which an alignment changes from a horizontal alignment to a vertical alignment, so that the color mixing between the adjacent sub-pixel areas may be prevented. Accordingly, a color purity and a color gamut of an image displayed by the organic light-emitting display device may be improved.

According to the present disclosure, the liquid crystal molecules of the liquid crystal layer disposed in the non-light-emitting portion equipped with the thin-film transistors and the like are in the tilted alignment, so that the reflection of the external light may be reduced.

Further, according to the present disclosure, the liquid crystal molecules are in the different alignments in the light-emitting portion and the non-light-emitting portion, so that the color mixing prevention and the external light reflection prevention may be achieved at the same time using a single liquid crystal layer.

DETAILED DESCRIPTION

A shape, a size, a ratio, an angle, a number, etc. disclosed in the drawings for describing the embodiments of the present disclosure are exemplary, and the present disclosure is not limited thereto. The same reference numerals refer to the same elements herein. Further, descriptions and details of well-known steps and elements are omitted for simplicity of the description. Furthermore, in the following detailed description of the present disclosure, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it will be understood that the present disclosure may be practiced without these specific details. In other instances, well-known methods, procedures, components, and circuits have not been described in detail so as not to unnecessarily obscure aspects of the present disclosure.

Hereinafter, an organic light-emitting display device according to various embodiments of the present disclosure will be described in detail.

FIG.1is a plan view schematically showing a configuration of an organic light-emitting display device according to one embodiment of the present disclosure. However, connection and arrangement relationships between components of the organic light-emitting display device according to one embodiment of the present disclosure are not limited thereto.FIG.2is a plan view schematically showing a display panel of an organic light-emitting display device according to one embodiment of the present disclosure.

Referring toFIGS.1and2, an organic light-emitting display device100may include a display panel110, a timing controller124, a data driver120, and a gate driver113.

The display panel110may include a display area DA that includes pixel arrays to display an image and non-display areas NDA that do not display the image.

The non-display areas NDA may be disposed to surround the display area DA. The gate driver113, a data drive IC pad DPA, and various lines may be disposed in the non-display area NDA. The non-display area NDA may correspond to a bezel.

The display panel110may include a plurality of pixel areas P formed by a plurality of gate lines GL disposed in one direction and a plurality of data lines DL disposed in the other direction to be orthogonal to the gate lines GL.

The pixel areas P may be arranged in a matrix form, and each pixel area P may include a plurality of sub-pixel areas SP. Each pixel area P may include, for example, a red sub-pixel area SP_R, a green sub-pixel area SP_G, and a blue sub-pixel area SP_B.

The gate driver113controls on/off of driving thin-film transistors of the pixels in response to a gate control signal applied from the timing controller124, and ensures that a data voltage applied from the data driver120is provided to an appropriate pixel circuit. To this end, the gate driver113sequentially outputs gate signals such as scan signals or light-emitting signals, and sequentially supplies the gate signals to the gate lines GL.

The gate driver113may include at least one gate driver integrated circuit (gate driver IC), and may be located on one side or each of both sides of the display panel110depending on a driving method or a design method of the display panel110.

As for the gate driver113, as shown inFIG.1, the gate driver integrated circuit may be directly formed on the display panel110in a gate driver in panel (GIP) scheme. The gate driver113formed using the GIP scheme may be disposed in each non-display area NDA, which is each of left and right areas disposed outwardly of the display area DA. Further, the gate driver integrated circuit may be connected to a bonding pad of the display panel110in a tape automated bonding (TAB) scheme or a chip-on-glass (COG) scheme, or implemented in a chip-on film (COF) scheme.

The data driver120converts image data received from the timing controller124into an analog data voltage when a specific gate line GL is opened, and supplies the data voltage to the data line DL in synchronization with the gate control signal.

The data driver120may include at least one source driver integrated circuit (source driver IC)121to drive a number of data lines DL. Each source driver integrated circuit121may be connected to the bonding pad of the display panel110in the tape automated bonding (TAB) scheme or the chip-on-glass (COG) scheme, or directly placed or integrated on the display panel110. Further, each source driver integrated circuit121may be implemented in the chip on film (COF) scheme. For example, as shown inFIG.1, each source driver integrated circuit121is mounted on a flexible film123. One end of the flexible film123is bonded to at least one control printed circuit board150, and the other end thereof is bonded to a data drive IC pad DPA of the display panel110.

Accordingly, lines connecting the data drive IC pad DPA of the display panel110with the source driver integrated circuit121, and lines connecting the data drive IC pad DPA with lines of the control printed circuit board125may be formed on the flexible film123.

A number of circuits implemented with driving chips may be mounted on the control printed circuit board125. For example, the timing controller124may be placed on the control printed circuit board125as shown inFIG.1. In addition, on the control printed circuit substrate125, a power controller that supplies various voltages or currents to the display panel110, the data driver120, and the gate driver113or controls the various voltages or currents to be supplied may be further disposed.

The timing controller124provides the gate control signal to the gate driver113, and provides the data control signal to the data driver120to control the data driver120and the gate driver113.

Further, the timing controller124starts scan based on a timing implemented in each frame, converts an input image data input from the outside based on a data signal format used by the data driver120to output the converted image data, and control data driving at an appropriate time based on the scan.

FIG.3is a plan view schematically showing a pixel area of an organic light-emitting display device according to one embodiment of the present disclosure, which schematically shows a plane of the pixel area of a three-color (R, G, B) organic light-emitting display device.

Referring toFIG.3, signal lines including a gate line GL, a data line DL and a driving voltage line VDD are disposed on the first substrate105. The gate line GL crosses the data line DL and the driving voltage line VDD. The gate line GL may extend in a y-axis direction, and the data line DL and the driving voltage line VDD may extend in a x-axis direction.

According to the present embodiment, on the first substrate105, a red sub-pixel area SP_R, a green sub-pixel area SP_G, and a blue sub-pixel area SP_B may be defined by the aforementioned signal lines. The first substrate105may include the red sub-pixel area SP_R, the green sub-pixel area SP_G, and the blue sub-pixel area SP_B defined by the above-described signal lines.

For example, the red sub-pixel area SP_R and the blue sub-pixel area SP_B may be defined by two gate lines GL extending parallel to each other and the driving voltage line VDD and the data line DL crossing the gate lines GL. Further, the green sub-pixel area SP_G may be defined by two gate lines GL extending parallel to each other and two data lines DL intersecting the same. An arrangement order of the sub-pixel areas, and a type and the number of signal lines extending between the adjacent sub-pixel areas are not limited to the drawing and may be changed.

The red sub-pixel area SP_R, the green sub-pixel area SP_G, and the blue sub-pixel area SP_B defined on the first substrate105contain a red light-emitting area EA_R, a green light-emitting area EA_G, and a blue light-emitting area EA_B, respectively. In addition to the light-emitting area, each sub-pixel area includes a driving circuit area in which the thin-film transistor TFT and the like are placed. The red sub-pixel area SPR includes the red light-emitting area EA_R and the driving circuit area, the green sub-pixel area SP_G includes the green light-emitting area EA_G and the driving circuit area, and the blue sub-pixel area SP_B includes the blue light-emitting area EA_B and the driving circuit area.

The red light-emitting area EA_R, the blue light-emitting area EA_B, and the green light-emitting area EA_G may be defined by a bank190(seeFIG.4). The red light-emitting area EA_R, the green light-emitting area EA_G, and the blue light-emitting area EA_B may correspond to opening areas of the bank190, respectively. The signal lines and the driving circuit areas described above may be covered by the bank190. That is, the signal lines and the driving circuit areas described above may be placed beneath the bank190so as to overlap with the bank190.

Further, the first substrate105includes light-emitting portions EA and non-light-emitting portions NEA. The light-emitting portions EA and the non-light-emitting portions NEA may be arranged in a manner in which each light-emitting portion EA and each non-light-emitting portion NEA are alternately arranged with each other in the x-axis direction, that is, the direction in which the data line DL extends. Each of the light-emitting portion EA and the non-light-emitting portion NEA may be a portion of the first substrate105extending in the y-axis direction, that is, in the direction in which the gate line GL extends. The light-emitting portion EA may include, for example, the red light-emitting area EA_R, the blue light-emitting area EA_B, and the green light-emitting area EA_G. The non-light-emitting portions NEA may include the driving circuit areas including the thin-film transistor TFTs and the like. Further, the gate line GL may be disposed in the non-light-emitting portion NEA. The driving circuit area of the sub-pixel area may be referred to as the non-light-emitting area.

FIG.4is a cross-sectional view showing an organic light-emitting display device cut along A-A′ and A′-A″ cutting lines inFIG.3. In particular, a cross section cut along the A-A′ cutting line in this drawing represents a cross section of the non-light-emitting portion NEA equipped with the thin-film transistor TFT of the organic light-emitting display device according to one embodiment of the present disclosure and a portion of the light-emitting portion EA. Further, a cross section cut according to the A′-A″ cutting line represents a cross section of the light-emitting portions EA of the organic light-emitting display device according to one embodiment of the present disclosure.

On the substrate105, a light-blocking layer LS, a buffer layer130, the thin-film transistor TFT, an interlayer insulating layer140, a first passivation layer150, a first planarization layer155, the bank190, a first electrode160, an organic light-emitting layer170, a second electrode180, a second passivation layer250, color filters CF_R, CF_B, and CF_G, a second planarization layer280, a first alignment layer310, a liquid crystal layer350, a second alignment layer370, a second substrate450, a polarization layer500, and the like may be disposed.

The light-blocking layer LS may be disposed on the first substrate105to overlap an active layer A of the thin-film transistor TFT. The light-blocking layer LS may be made of a metal such as molybdenum (Mo), aluminum (Al), chromium (Cr), and silver (Ag), or an alloy thereof. However, the present disclosure is not limited thereto. The light-blocking layer LS may be made of various materials known in the art. The light-blocking layer LS may prevent external light from invading the active layer A of the thin-film transistor TFT.

The buffer layer130may be disposed on the light-blocking layer LS and cover the light-blocking layer LS. According to an example, the buffer layer130may be formed by stacking a plurality of inorganic layers. For example, the buffer layer130may be formed of a multilayer in which at least two inorganic layers among a silicon oxide layer SiOX, a silicon nitride layer SiNX, and a silicon oxynitride layer SiON are stacked vertically. This buffer layer130may be formed on an entire top face of the first substrate105to prevent moisture from penetrating into the organic light-emitting element through the first substrate105.

The thin-film transistor TFT may be disposed on the buffer layer130. According to an example, the thin-film transistor TFT may include the active layer AC, a gate electrode G, a drain electrode D, and a source electrode S. The active layer AC may be disposed on the buffer layer130so as to overlap with the light-blocking layer LS. The active layer AC may be in direct contact with source electrode S and the drain electrode D. The active layer AC may face the gate electrode G while the gate insulating film GI may be interposed therebetween. The gate insulating film GI may only be disposed between the gate electrode G and the active layer AC. Alternatively, the film GI may be disposed on the active layer AC and the buffer layer130. The gate electrode G may be disposed on the gate insulating film GI. The gate electrode G may overlap with the active layer AC while the gate insulating film GI is interposed therebetween.

The interlayer insulating layer140may be disposed on the gate electrode G, the active layer AC, and the buffer layer130. The interlayer insulating film140may protect the thin-film transistor TFT and may insulate the drain electrode D and the source electrode S from the gate electrode G. The interlayer insulating layer140may be partially removed to allow contact between the active layer AC and the source electrode S or the drain electrode D. For example, the interlayer insulating layer140may include contact holes through which the source electrode S and the drain electrode D pass.

The drain electrode D and the source electrode S may be spaced apart from each other and disposed on the interlayer insulating layer140. The drain electrode D may contact one side of the active layer AC via one contact hole provided in the interlayer insulating layer140, while the source electrode S may contact the opposite side of the active layer AC via the opposite contact hole provided in the interlayer insulating layer140.

FIG.4shows that the thin-film transistor TFT has a top gate structure. However, the present disclosure is not limited thereto. The thin-film transistor TFT may have a bottom gate structure, or a double gate structure.

The signal lines defining each sub-pixel area may be located on the interlayer insulating layer140. For example, the data lines DL may be located between the red light-emitting area EA_R and the blue light-emitting area EA_B and between the blue light-emitting area EA_B and the green light-emitting area EA_G. The driving voltage line VDD may be located between the green light-emitting area EA_G and the adjacent red light-emitting area EA_R.

The first passivation layer150may be disposed on the interlayer insulating layer140and the thin-film transistor TFT. The first passivation layer150may protect the thin-film transistor TFT. The first passivation layer150may be made of an inorganic insulating material such as silicon oxide and silicon nitride, or an organic insulating material such as photoacrylic or benzocyclobutene.

The first planarization layer155may be disposed on the first passivation layer150to remove an unevenness caused by the, thin-film transistor TFT and the like. The first planarization layer155may be made of an organic insulating material such as photoacrylic or benzocyclobutene.

On the first planarization layer155, the first electrode160electrically connected to the source electrode S of the thin-film transistor TFT through the first planarization layer155and the first passivation layer150is disposed.

The bank190is disposed along an edge of the first electrode160to define light-emitting areas. Specifically, a first bank area190aof the bank190may be disposed in the light-emitting portion EA, and a second bank area190bof the bank190may be disposed in the non-light-emitting portion NEA. Referring toFIG.8, the first bank areas190amay be arranged alternately with the light-emitting areas in the y-axis direction. The first bank areas190amay be disposed between the red light-emitting area EA_R and the green light-emitting area EA_G, between the green light-emitting area EA_G and the blue light-emitting area EA_B, and between the blue light-emitting area EA_B and the red light-emitting area EA_R, respectively. The second bank area190bmay extend in the y-axis direction, and may be placed between two adjacent red light-emitting areas EA_R, between two adjacent green light-emitting areas EA_G, and between two adjacent blue light-emitting areas EA_B. A thickness of the second bank area190bmay be greater than that of the first bank area190a. As such, by making the thickness of the second bank area190blarger than that of the first bank area190a, a thickness of a portion of the liquid crystal layer350disposed in the non-light-emitting portion NEA may be made smaller than that of the remaining portion of the liquid crystal layer350disposed in the light-emitting portion EA.

The organic light-emitting layer170and the second electrode180are sequentially stacked on the bank190and the first electrode160. In this connection, the first electrode160, the organic light-emitting layer170, and the second electrode180constitute an organic light-emitting element. The organic light-emitting layer170may emit white light. In particular, the organic light-emitting layer170may emit white light linearly polarized in the y-axis direction, for example. The organic light-emitting layer170will be described later with reference toFIGS.5and6.

The second passivation layer250may be disposed on the second electrode180. The second passivation layer250may protect the second electrode180. The second passivation layer250may be made of an inorganic insulating material such as silicon oxide and silicon nitride, or may be made of an organic insulating material such as photoacrylic or benzocyclobutene.

In the light-emitting portion EA, the color filters CF_R, CF_G, and CF_B may be disposed on the second passivation layer250. The red light-emitting area EA_R is equipped with the red color filter CF_R, the green light-emitting area EA_G is equipped with the green color filter CF_G, and the blue light-emitting area EA_B is equipped with the blue color filter CF_B.

A second planarization layer280that covers the color filters CF_R, CF_G, and CF_B may be disposed on the second passivation layer250.

The first alignment layer310, the liquid crystal layer350, and the second alignment layer370may be sequentially stacked on the second planarization layer280.

The liquid crystal layer350may include, for example, positive c-plate liquid crystal molecules. A refractive index anisotropy Δn of the liquid crystal molecules may be 0.05 to 0.2.

The first alignment layer310and liquid crystal layer350may be placed in both of the light-emitting portion EA and the non-light-emitting portion NEA, and the first alignment layer370may only be placed in the non-light-emitting portion NEA. The first alignment layer310and the second alignment layer370may be made of polyimide. The first alignment layer310and the second alignment layer370may be aligned in the same direction. For example, as shown inFIG.7, the first alignment layer310and the second alignment layer370may be aligned in the y-axis direction. For this reason, liquid crystal molecules of the portion of the liquid crystal layer350placed in the light-emitting portion EA including the light-emitting areas and liquid crystal molecules of the portion of the liquid crystal layer350placed in the non-light-emitting portion NEA including the non-light-emitting areas may be aligned in different alignments. The liquid crystal molecules of the portion of the liquid crystal layer350placed in the light-emitting portion EA including the light-emitting areas may be in a hybrid alignment (also, referred to as a splay alignment) in which the alignment is changed from a horizontal alignment to a vertical alignment from a bottom to a top of the liquid crystal layer350. The liquid crystal molecules of the portion of the liquid crystal layer350placed in the non-light-emitting portion NEA including the non-light-emitting areas may be in a tilted alignment of having, for example, a slope of 45 degrees with respect to a top face of the first alignment layer310.

A thickness d1of the portion of the liquid crystal layer350disposed in the light-emitting portion EA including the light-emitting areas may be greater than a thickness d2of the portion of the liquid crystal layer350disposed in the non-light-emitting portion NEA including the non-light-emitting areas. For example, the thickness d1of the portion of the liquid crystal layer350disposed in the light-emitting portion EA including the light-emitting areas may be three times the thickness d2of the portion of the liquid crystal layer350disposed in the non-light-emitting portion NEA including the non-light-emitting areas. For example, when the refractive index anisotropy Δn of the liquid crystal molecules is 0.13, he thickness d1of the portion of the liquid crystal layer350disposed in the light-emitting portion EA including the light-emitting areas may be 3.3 μm, and the thickness d2of the portion of the liquid crystal layer350disposed in the non-light-emitting portion NEA including the non-light-emitting areas may be 1.1 μm.

Accordingly, the portion of the liquid crystal layer350placed in the light-emitting portion EA including the light-emitting areas may have a phase delay of λ/2 with respect to a viewing angle of 45 degrees, and the portion of the liquid crystal layer350placed in the non-light-emitting portion NEA including the non-light-emitting areas may have a phase delay of214with respect to a front side.

The second substrate450may be disposed on the second alignment layer370and the liquid crystal layer350. The second substrate450may be a glass substrate. It may be understood that the second alignment layer370is disposed on an area of the second substrate450corresponding to the non-light-emitting portion NEA, including the non-light-emitting areas of the first substrate105.

The polarization layer500is disposed on the second substrate450. The polarization layer500may be aligned in the x-axis direction so as to transmit light linearly polarized in the y-axis direction. Thus, the polarization layer500may transmit the white light linearly polarized in the y-axis direction, which is emitted from the organic light-emitting layer170.

Thus, according to one embodiment of the present disclosure, because the portion of the liquid crystal layer350disposed in the light-emitting portion EA including the light-emitting areas has the phase delay of λ/2 with respect to the viewing angle of 45 degrees, the light linearly polarized in the y-axis direction, which is emitted from the organic light-emitting layer170, is converted into light linearly polarized in the x-axis direction by λ/2 while passing through the liquid crystal layer350, and is blocked by the polarization layer500on the top face of the second substrate450. Accordingly, color mixing between the sub-pixel areas may be prevented in the light-emitting portion EA.

In addition, according to one embodiment of the present disclosure, because the portion of the liquid crystal layer350disposed in the non-light-emitting portion NEA including the non-light-emitting areas has the phase delay of λ/4 with respect to the front side, in the non-light-emitting portion NEA, external light passes through the polarization layer500on the top face of the second substrate450and is linearly polarized in the y-axis direction, then, is right-circularly polarized by λ/4 while passing through the liquid crystal layer350, then, is internally reflected again and left-circularly polarized, then, is converted into light linearly polarized in the x-axis direction by λ/4 while passing through the liquid crystal layer350, and then, is blocked by the polarization layer500disposed on the top face of the second substrate450. Accordingly, reflection of the external light may be prevented in the non-light-emitting portion NEA.

FIG.5is a cross-sectional view showing an organic light-emitting element of an organic light-emitting display device according to one embodiment of the present disclosure.FIG.6is a plan view showing an alignment of light-emitting alignment layers in an organic light-emitting element according to one embodiment of the present disclosure.

As shown inFIG.5, the organic light-emitting layer170is composed of a charge generating layer CGL, and a first light-emitting unit170aand a second light-emitting unit170bformed with the charge generating layer CGL interposed therebetween. The first light-emitting unit170aincludes first hole injection layer HILL a first hole transport layer HTL1, a first light-emitting alignment layer AL1, a first light-emitting layer EML1, and a first electron transport layer ETL1. The second light-emitting unit170bincludes a second hole injection layer HIL2, a second hole transport layer HTL2, a second light-emitting alignment layer AL2, a second light-emitting layer EML2, and a second electron transport layer ETL2. The first light-emitting layer EML1of the first light-emitting unit170aincludes a fluorescent host containing a blue dopant to emit blue light in a range of 400 nm to 490 nm, and the second light-emitting layer EML2of the second light-emitting unit134bincludes a yellow-green dopant and a phosphorescent host to emit yellow-green light in a range of 500 nm to 640 nm. In particular, the first light-emitting alignment layer AL1and the second light-emitting alignment layer AL2may be made of polyimide, and may be, for example, aligned in the y-axis direction. Accordingly, the first light-emitting unit170aformed on the first light-emitting alignment layer AL1emits blue light linearly polarized in the y-axis direction, and the second light-emitting unit170bformed on the second light-emitting alignment layer AL2emits yellow-green light linearly polarized in the y-axis direction. Therefore, the blue light of the first light-emitting unit170aand the yellow-green light of the second light-emitting unit170bare mixed with each other, so that the organic light-emitting layer170may emit white light linearly polarized in the y-axis direction.

In addition, the organic light-emitting layer170may implement white light using other fluorescent and phosphorescent dopants. For example, the first light-emitting layer EML1may be composed of a blue light-emitting layer, and the second light-emitting layer EML2may be composed of a red light-emitting layer and a green light-emitting layer.

So far, with reference to the drawings, the three-color (R, G, B) organic light-emitting display device including the red, green, and blue sub-pixel areas has been described. However, the technical idea of the present disclosure may also be applied to a four-color (R, W, G, and B) organic light-emitting display device including red, white, green, and blue sub-pixel areas.

Embodiments of the present disclosure may be described as follows.

A first aspect of the present disclosure provides an organic light-emitting display device comprising: a first substrate having sub-pixel areas, wherein each sub-pixel area includes light-emitting area and non-light-emitting area; thin-film transistors respectively disposed in non-light-emitting areas of the sub-pixel areas; a first planarization layer disposed in the sub-pixel areas while covering the thin-film transistors; organic light-emitting elements disposed on the first planarization layer and disposed in light-emitting areas of the sub-pixel areas; a liquid crystal layer disposed on the organic light-emitting elements and disposed in the sub-pixel areas and in an area between the sub-pixel areas; and a second substrate disposed on the liquid crystal layer. Liquid crystal molecules of the liquid crystal layer disposed in the light-emitting areas are in a hybrid alignment. In the hybrid alignment, an alignment of the liquid crystal molecules gradually changes from a horizontal alignment to a vertical alignment. In addition, liquid crystal molecules of the liquid crystal layer disposed in the non-light-emitting areas are in a tilted alignment.

In one implementation of the first aspect, the device further comprises: a polarization layer disposed on the second substrate, and the polarization layer transmits light linearly polarized in a first direction, and organic light-emitting layers of the organic light-emitting elements emit white light linearly polarized in the first direction.

In one implementation of the first aspect, the organic light-emitting layers include a first light-emitting alignment layer aligned in the first direction, a first light-emitting layer disposed on the first light-emitting alignment layer, a second light-emitting alignment layer aligned in the first direction, and a second light-emitting layer disposed on the second light-emitting alignment layer.

In one implementation of the first aspect, portions of the liquid crystal layer respectively disposed in the light-emitting areas have a phase delay of λ/2 with respect to a viewing angle of 45 degrees, and portions of the liquid crystal layer respectively disposed in the non-light-emitting areas have a phase delay of λ/4 with respect to a front side.

In one implementation of the first aspect, portions of the liquid crystal layer respectively disposed in the light-emitting areas have a thickness greater than a thickness of portions of the liquid crystal layer respectively disposed in the non-light-emitting areas.

In one implementation of the first aspect, the thickness of the portions of the liquid crystal layer disposed in the light-emitting areas is three times the thickness of the portion of the liquid crystal layer disposed in the non-light-emitting areas.

In one implementation of the first aspect, the device further comprises: color filters respectively disposed on the organic light-emitting elements; a second planarization layer covering the color filters; a first alignment layer disposed on the second planarization layer; and a second alignment layer disposed on areas of the second substrate corresponding to the non-light-emitting areas of the first substrate. The liquid crystal layer is disposed between the first alignment layer and the second substrate.

In one implementation of the first aspect, the first alignment layer and the second alignment layer are aligned in the first direction.

The organic light-emitting display device of claim2, wherein the device further comprises: a bank disposed on the top face of the first planarization layer, wherein the bank defines the light-emitting areas, and the bank includes first bank areas alternately arranged with the light-emitting areas in the first direction, and second bank areas respectively disposed in the non-light-emitting areas and extending in the first direction. A thickness of the first bank areas is smaller than a thickness of the second bank areas.

A second aspect of the present disclosure provides an organic light-emitting display device comprising: a first substrate including light-emitting portions and non-light-emitting portions; thin-film transistors disposed in each non-light-emitting portion; a first planarization layer disposed on the first substrate while covering the thin-film transistors; organic light-emitting elements disposed on the first planarization layer and disposed in the light-emitting portions, wherein the organic light-emitting elements emit white light linearly polarized in a first direction; a liquid crystal layer disposed on the organic light-emitting elements and disposed in the light-emitting portions and the non-light-emitting portions; and a second substrate disposed on the liquid crystal layer. Liquid crystal molecules of the liquid crystal layer disposed in the light-emitting portion are in a hybrid alignment. In the hybrid alignment, an alignment of the liquid crystal molecules gradually changes from a horizontal alignment to a vertical alignment. In addition, liquid crystal molecules of the liquid crystal layer disposed in the non-light-emitting portion are in a tilted alignment.

In one implementation of the second aspect, the device further comprises: a polarization layer disposed on the second substrate, and the polarization layer transmits the light linearly polarized in the first direction.

In one implementation of the second aspect, organic light-emitting layers of the organic light-emitting elements include at least one light-emitting alignment layer aligned in the first direction and at least one light-emitting layer.

In one implementation of the second aspect, portions of the liquid crystal layer respectively disposed in the light-emitting portions have a thickness greater than a thickness of portions of the liquid crystal layer respectively disposed in the non-light-emitting portions.

In one implementation of the second aspect, the thickness of the portions of the liquid crystal layer disposed in the light-emitting portions is three times the thickness of the portion of the liquid crystal layer disposed in the non-light-emitting portions.

In one implementation of the second aspect, the device further comprises: color filters respectively disposed on the organic light-emitting elements; a second planarization layer covering the color filters; a first alignment layer disposed on the second planarization layer; and a second alignment layer disposed on areas of the second substrate corresponding to the non-light-emitting portions of the first substrate. The liquid crystal layer is disposed between the first alignment layer and the second substrate.

In one implementation of the second aspect, the first alignment layer and the second alignment layer are aligned in the first direction.

In one implementation of the second aspect, the device further comprises: a bank disposed on the first planarization layer, wherein the bank defines the light-emitting areas of the light-emitting portion, and the bank includes first bank areas alternately arranged with the light-emitting areas of the light-emitting portion in the first direction, and second bank areas disposed in the non-light-emitting portion and extending in the first direction. A thickness of the first bank areas is smaller than a thickness of the second bank areas.