KR102656493B1 - Display Device - Google Patents

Abstract

A display device according to an embodiment of the present invention includes a first substrate, a thin film transistor, an organic light emitting diode, a second substrate, and quantum dots. The thin film transistor is located on the first substrate, and the organic light emitting diode is connected to the thin film transistor. The second substrate seals the organic light emitting diode and faces the first substrate. Quantum dots are included in a first or second substrate disposed in a direction in which light is emitted from the organic light emitting diode.

Description

Display Device {Display Device}

The present invention relates to a display device, and more specifically to a display device using quantum dots.

As the information society develops, the demand for display devices for displaying images is increasing in various forms. The display device field has been rapidly changing toward thin, light, large-area flat panel displays (FPDs) replacing bulky cathode ray tubes (CRTs). Flat panel displays include Liquid Crystal Display Device (LCD), Plasma Display Panel (PDP), Organic Light Emitting Display Device (OLED), and Electrophoretic Display Device. : ED), etc.

Among these, organic light emitting display devices are self-emitting devices that emit light on their own and have the advantages of fast response speed, high luminous efficiency, brightness, and viewing angle. In particular, organic light emitting display devices can not only be formed on flexible plastic substrates, but can also be driven at lower voltages and consume relatively less power than plasma display panels or inorganic electroluminescence (EL) displays. It has the advantage of being small and having excellent color.

However, as customer demands for high-quality color gamut continue to increase, there is a need to develop high-quality organic light emitting display devices to satisfy customer needs.

The present invention provides a display device that can improve color gamut and display quality using quantum dots.

To achieve the above object, a display device according to an embodiment of the present invention includes a first substrate, a thin film transistor, an organic light emitting diode, a second substrate, and quantum dots. The thin film transistor is located on the first substrate, and the organic light emitting diode is connected to the thin film transistor. The second substrate seals the organic light emitting diode and faces the first substrate. Quantum dots are included in a first or second substrate disposed in a direction in which light is emitted from the organic light emitting diode.

Light from the organic light emitting diode is emitted to the first substrate, and a plurality of quantum dots are included in the first substrate.

It further includes a color filter disposed between the organic light emitting diode and the first substrate.

The color filter includes at least one of red, green, blue, and white color filters, and the plurality of quantum dots overlap with at least one of the red, green, blue, and white color filters.

A plurality of quantum dots are included throughout the first substrate.

The plurality of quantum dots include active quantum dots and inactive quantum dots.

It further includes a UV absorption layer disposed between the organic light emitting diode and the first substrate.

Light from the organic light emitting diode is emitted to the second substrate, and a plurality of quantum dots are included in the second substrate.

It further includes a color filter disposed between the organic light emitting diode and the second substrate.

The color filter includes at least one of red, green, blue, and white color filters, and the plurality of quantum dots overlap with at least one of the red, green, blue, and white color filters.

A plurality of quantum dots are included throughout the second substrate.

The plurality of quantum dots include active quantum dots and inactive quantum dots.

It further includes a UV absorption layer disposed between the organic light emitting diode and the second substrate.

Display devices according to embodiments of the present invention have the advantage of improving color gamut by improving color purity of a specific color without having a separate quantum dot layer by forming quantum dots in a substrate through which light is emitted.

1 is a schematic block diagram of an organic light emitting display device.
Figure 2 is a first example diagram showing the circuit configuration of a subpixel.
Figure 3 is a second example diagram showing the circuit configuration of a subpixel.
Figure 4 is a plan view showing an organic light emitting display device according to an embodiment of the present invention.
Figure 5 is a cross-sectional view of a subpixel area of an organic light emitting display device according to a first embodiment of the present invention.
Figure 6 is a cross-sectional view schematically showing an organic light emitting display device according to a first embodiment of the present invention.
Figure 7 is a graph showing the absorption rate by wavelength according to temperature during heat treatment of PbTe quantum dots.
Figure 8 is a cross-sectional view of a subpixel area of an organic light emitting display device according to another first embodiment of the present invention.
Figure 9 is a cross-sectional view schematically showing an organic light emitting display device according to another first embodiment of the present invention.
Figures 10 and 11 are diagrams showing a laser irradiation process for quantum dots according to the first embodiment of the present invention.
Figure 12 is a cross-sectional view schematically showing an organic light emitting display device according to a second embodiment of the present invention.
Figure 13 is a cross-sectional view of a subpixel area of an organic light emitting display device according to another second embodiment of the present invention.
Figure 14 is an image of quantum dots.
Figure 15 is a graph showing the radius of quantum dots according to heat treatment time.

Hereinafter, preferred embodiments of the present invention will be described with reference to the attached drawings. Like reference numerals refer to substantially the same elements throughout the specification. In the following description, if it is determined that a detailed description of a known technology or configuration related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description will be omitted. Additionally, the component names used in the following description may have been selected in consideration of ease of specification preparation, and may be different from the component names of the actual product.

The display device according to the present invention can be an organic light emitting display device, a liquid crystal display device, an electrophoretic display device, etc., but the present invention will describe an organic light emitting display device as an example. The organic light emitting display device includes an organic film layer made of organic material between a first electrode, which is an anode, and a second electrode, which is a cathode. Therefore, the holes supplied from the first electrode and the electrons supplied from the second electrode combine within the organic layer to form excitons, which are hole-electron pairs, and emit light by the energy generated when the excitons return to the ground state. It is a self-luminous display device.

Hereinafter, embodiments of the present invention will be described with reference to the attached drawings.

FIG. 1 is a schematic block diagram of an organic light emitting display device, FIG. 2 is a first example diagram showing the circuit configuration of a subpixel, and FIG. 3 is a second example diagram showing the circuit configuration of a subpixel.

Referring to FIG. 1, the organic light emitting display device includes an image processing unit 10, a timing control unit 20, a data driver 30, a gate driver 40, and a display panel 50.

The image processing unit 10 outputs a data enable signal (DE) in addition to a data signal (DATA) supplied from the outside. The image processing unit 10 may output one or more of a vertical synchronization signal, a horizontal synchronization signal, and a clock signal in addition to the data enable signal DE, but these signals are omitted for convenience of explanation. The image processing unit 10 is formed in the form of an integrated circuit (IC) on a system circuit board.

The timing control unit 20 receives a data enable signal (DE) or a driving signal including a vertical synchronization signal, a horizontal synchronization signal, and a clock signal, as well as a data signal (DATA) from the image processing unit 10.

The timing control unit 20 includes a gate timing control signal (GDC) for controlling the operation timing of the gate driver 40 and a data timing control signal (DDC) for controlling the operation timing of the data driver 30 based on the driving signal. outputs. The timing control unit 20 is formed in the form of an IC on a control circuit board.

The data driver 30 samples and latches the data signal DATA supplied from the timing control unit 20 in response to the data timing control signal DDC supplied from the timing control unit 20, converts it to a gamma reference voltage, and outputs it. . The data driver 30 outputs a data signal DATA through the data lines DL1 to DLn. The data driver 30 is attached in the form of an IC on a substrate.

The gate driver 40 outputs a gate signal while shifting the level of the gate voltage in response to the gate timing control signal (GDC) supplied from the timing controller 20. The gate driver 40 outputs a gate signal through the gate lines GL1 to GLm. The gate driver 40 is formed in the form of an IC on a gate circuit board or in the form of a gate in panel (GIP) on the display panel 50.

The display panel 50 displays images in response to the data signal (DATA) and gate signal supplied from the data driver 30 and the gate driver 40. The display panel 50 includes subpixels (SP) that display images.

Referring to FIG. 2, one subpixel includes a switching transistor (SW), a driving transistor (DR), a compensation circuit (CC), and an organic light emitting diode (OLED). An organic light emitting diode (OLED) operates to emit light according to a driving current formed by a driving transistor (DR).

The switching transistor SW performs a switching operation in response to the gate signal supplied through the gate line GL1 so that the data signal supplied through the first data line DL1 is stored as a data voltage in the capacitor Cst. The driving transistor (DR) operates so that a driving current flows between the high-potential power line (VDD) and the low-potential power line (GND) according to the data voltage stored in the capacitor (Cst). The compensation circuit (CC) is a circuit for compensating the threshold voltage of the driving transistor (DR). Additionally, the capacitor connected to the switching transistor (SW) or driving transistor (DR) may be located inside the compensation circuit (CC). The compensation circuit (CC) consists of one or more thin film transistors and a capacitor. The composition of the compensation circuit (CC) varies greatly depending on the compensation method, so specific examples and descriptions thereof will be omitted.

In addition, as shown in FIG. 3, when the compensation circuit (CC) is included, the subpixel further includes a signal line and a power line for supplying a specific signal or power in addition to driving the compensation thin film transistor. The gate line GL1 includes a 1-1 gate line GL1a for supplying a gate signal to the switching transistor SW, and a 1-2 gate line GL1b for driving the compensation thin film transistor included in the subpixel. It can be included. And the added power line can be defined as an initialization power line (INIT) for initializing a specific node of a subpixel to a specific voltage. However, this is only an example and is not limited to this.

Meanwhile, in Figures 2 and 3, one subpixel includes a compensation circuit (CC) as an example. However, if the subject of compensation is located outside the subpixel, such as the data driver 30, the compensation circuit (CC) may be omitted. In other words, one subpixel is basically composed of a 2T (Transistor) 1C (Capacitor) structure including a switching transistor (SW), a driving transistor (DR), a capacitor, and an organic light emitting diode (OLED), but the compensation circuit (CC) If added, it may be configured in various ways such as 3T1C, 4T2C, 5T2C, 6T2C, 7T2C, etc. In addition, in Figures 2 and 3, the compensation circuit (CC) is shown as being located between the switching transistor (SW) and the driving transistor (DR), but it can also be located between the driving transistor (DR) and the organic light-emitting diode (OLED). It may be possible. The location and structure of the compensation circuit (CC) are not limited to FIGS. 2 and 3.

Figure 4 is a plan view showing an organic light emitting display device according to an embodiment of the present invention.

Referring to FIG. 4, the organic light emitting display device includes a flexible substrate (PI), a display portion (A/A), and a GIP driver (GIP) disposed on the right side of the flexible substrate (PI) in addition to the display portion (A/A), and a flexible substrate. It includes a pad portion (PD) disposed below (PI). The display unit (A/A) has a plurality of subpixels (SP) arranged and emits R, G, B or R, G, B, W to implement full color. For example, on the right side of the display unit (A/A), a GIP driver (GIP) is disposed to apply a gate drive signal to the display unit (A/A). The pad portion PD is disposed on one side, for example, below the display portion A/A, and chip-on-films (COFs) are attached to the pad portion PD. A data signal and power supplied through a chip-on-film (COF) are applied to a plurality of signal lines (not shown) connected from the display unit (A/A).

Hereinafter, various embodiments of the present invention will be described with reference to the subpixel (SP) area of the organic light emitting display device of the present invention.

<First Example>

Figure 5 is a cross-sectional view of the subpixel area of the organic light emitting display device according to the first embodiment of the present invention, Figure 6 is a cross-sectional view schematically showing the organic light emitting display device according to the first embodiment of the present invention, and Figure 7 is It is a graph showing the absorption rate by wavelength according to temperature during heat treatment of PbTe quantum dots, Figure 8 is a cross-sectional view of the subpixel area of an organic light emitting display device according to another first embodiment of the present invention, and Figure 9 is a graph showing the absorption rate by wavelength according to temperature in heat treatment of PbTe quantum dots. This is a cross-sectional view schematically showing an organic light emitting display device according to an embodiment, and FIGS. 10 and 11 are diagrams showing a laser irradiation process for quantum dots according to the first embodiment of the present invention.

Referring to FIG. 5, in the organic light emitting display device according to the first embodiment of the present invention, the first buffer layer (BUF1) is located on the first substrate (SUB1). The first substrate SUB1 may be a transparent glass substrate. The first buffer layer (BUF1) serves to protect the thin film transistor (TFT) formed in a subsequent process from impurities such as alkali ions leaking from the first substrate (SUB1). The first buffer layer (BUF1) may be silicon oxide (SiOx), silicon nitride (SiNx), or a multilayer thereof.

The shield layer LS is located on the first buffer layer BUF1. The shield layer LS blocks light incident from the outside and prevents photo current from occurring in the semiconductor layer ACT. A second buffer layer (BUF2) is located on the shield layer (LS). The second buffer layer (BUF2) serves to protect the thin film transistor formed in a subsequent process from impurities such as alkali ions leaking from the shield layer (LS). The second buffer layer (BUF2) may be silicon oxide (SiOx), silicon nitride (SiNx), or a multilayer thereof.

The semiconductor layer (ACT) is located on the second buffer layer (BUF2). The semiconductor layer (ACT) may be made of a silicon semiconductor or an oxide semiconductor. Silicon semiconductors may include amorphous silicon or crystallized polycrystalline silicon. Here, polycrystalline silicon has high mobility (over 100㎠/Vs), low energy consumption and excellent reliability, so it can be applied to gate drivers and/or multiplexers (MUX) for driving elements or to driving TFTs within pixels. there is. Meanwhile, oxide semiconductors have low off-current, so they are suitable for switching TFTs that have a short on time and a long off time. In addition, since the off-current is small, the pixel voltage maintenance period is long, making it suitable for display devices that require low-speed driving and/or low power consumption. Additionally, the semiconductor layer ACT includes a drain region and a source region containing p-type or n-type impurities, and includes a channel between them.

A gate insulating film (GI) is located on the semiconductor layer (ACT). The gate insulating film (GI) may be silicon oxide (SiOx), silicon nitride (SiNx), or a multilayer thereof. A gate electrode (GA) is located on the gate insulating film (GI) in a certain area of the semiconductor layer (ACT), that is, at a position corresponding to a channel where impurities are injected. The gate electrode (GA) is selected from the group consisting of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu). It is formed from either one or an alloy thereof. In addition, the gate electrode (GA) is a group consisting of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu). It may be a multi-layer made of any one selected from or an alloy thereof. For example, the gate electrode GA may be a double layer of molybdenum/aluminum-neodymium or molybdenum/aluminum.

An interlayer dielectric (ILD) that insulates the gate electrode (GA) is located on the gate electrode (GA). The interlayer insulating layer (ILD) may be a silicon oxide layer (SiOx), a silicon nitride layer (SiNx), or a multilayer thereof. Contact holes (CH) exposing a portion of the semiconductor layer (ACT) are located in some areas of the interlayer insulating layer (ILD) and the gate insulating layer (GI).

A drain electrode (DE) and a source electrode (SE) are located on the interlayer insulating layer (ILD). The drain electrode (DE) is connected to the semiconductor layer (ACT) through a contact hole (CH) that exposes the drain region of the semiconductor layer (ACT), and the source electrode (SE) exposes the source region of the semiconductor layer (ACT). It is connected to the semiconductor layer (ACT) through the contact hole (CH). The source electrode (SE) and drain electrode (DE) may be made of a single layer or multiple layers. When the source electrode (SE) and drain electrode (DE) are a single layer, molybdenum (Mo), aluminum (Al), or chromium It may be made of any one selected from the group consisting of (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu), or an alloy thereof. In addition, when the source electrode (SE) and drain electrode (DE) are multilayers, a double layer of molybdenum/aluminum-neodymium, a triple layer of titanium/aluminum/titanium, molybdenum/aluminum/molybdenum, or molybdenum/aluminum-neodymium/molybdenum. It can be done. Accordingly, a thin film transistor (TFT) is constructed including a semiconductor layer (ACT), a gate electrode (GA), a drain electrode (DE), and a source electrode (SE).

A passivation film (PAS) is located on the first substrate (SUB1) including the thin film transistor (TFT). The passivation film (PAS) is an insulating film that protects the underlying device and may be a silicon oxide film (SiOx), a silicon nitride film (SiNx), or a multiple layer thereof. An overcoat layer (OC) is located on the passivation film (PAS). The overcoat layer (OC) may be a flattening film to alleviate steps in the lower structure, and is made of organic materials such as polyimide, benzocyclobutene series resin, and acrylate. The overcoat layer (OC) can be formed in a method such as SOG (spin on glass) in which the organic material is coated in a liquid form and then cured.

A via hole (VIA) exposing the drain electrode (DE) is located in some areas of the overcoat layer (OC). An organic light emitting diode (OLED) is located on the overcoat layer (OC). More specifically, the first electrode (ANO) is located on the overcoat layer (OC). The first electrode (ANO) acts as a pixel electrode and is connected to the drain electrode (DE) of the thin film transistor (TFT) through a via hole (VIA). The first electrode (ANO) is an anode and may be made of a transparent conductive material such as ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), or ZnO (Zinc Oxide). A reflective layer (RFL) is located below the first electrode (ANO). The reflective layer (RFL) serves to reflect the light transmitted through the first electrode (ANO) upward, and may be made of aluminum (Al), copper (Cu), silver (Ag), nickel (Ni), or an alloy thereof. and is preferably made of APC (silver/palladium/copper alloy).

A bank layer (BNK) dividing pixels is located on the first substrate (SUB1) including the first electrode (ANO). The bank layer (BNK) is made of organic materials such as polyimide, benzocyclobutene series resin, and acrylate. The bank layer (BNK) has a pixel definition portion (OP) that exposes the first electrode (ANO). An organic layer (EML) in contact with the first electrode (ANO) is located on the front surface of the first substrate (SUB1). The organic layer (EML) is a layer that emits light by combining electrons and holes, and may include a hole injection layer or hole transport layer between the organic layer (EML) and the first electrode (ANO), and may include a hole injection layer or a hole transport layer on the organic layer (EML). It may include an electron transport layer or an electron injection layer.

The second electrode (CAT) is located on the organic layer (EML). The second electrode (CAT) is located in front of the display unit (A/A), and as a cathode electrode, it can be made of magnesium (Mg), calcium (Ca), aluminum (Al), silver (Ag), or an alloy thereof with a low work function. there is. If the second electrode (CAT) is a transmission electrode, it is thin enough to allow light to pass through. A UV absorption layer (UVL) is located on the second electrode (CAT). The UV absorption layer (UVL) is used to block the UV laser irradiated to activate quantum dots (AQDs), which will be described later, and prevents the organic material of the organic layer (EML) from being damaged by the UV laser. The UV absorption layer (UVL) may have any thickness as long as it is thick enough to absorb UV. The UV absorption layer is composed of benzophenone-based (absorption range 300-380 nm), benzotriazole-based (absorption range 300-385 nm), salicylic acid-based (absorption range 260-340 nm), acrylonitrile-based (absorption range 290-400 nm), and organic nickel compounds. Or it may be made of mono benzoic acid type. However, the UV absorption layer (UVL) of the present invention is not limited to this and any material that absorbs UV in the wavelength range of a UV laser can be used.

The first substrate (SUB1) on which the thin film transistor (TFT) and the organic light emitting diode (OLED) are formed is sealed with the second substrate (SUB2) through an adhesive layer (ADL). The second substrate SUB2 may be a transparent glass substrate like the first substrate SUB1. A color filter (CF) and a black matrix (BM) are located on the lower surface of the second substrate (SUB2). A color filter (CF) converts white light emitted from an organic light-emitting diode (OLED) into red, green, and blue, and white light passes through areas where red, green, and blue are not placed, creating white. The black matrix (BM) prevents light from being mixed with adjacent color filters (CF) of different colors and serves to partition each subpixel.

Meanwhile, in the first embodiment of the present invention, a plurality of quantum dots (AQDs) are included in the second substrate (SUB2). Quantum dots (AQDs) are materials with a crystal structure several nanometers in size and are composed of hundreds to thousands of atoms. This small-sized material has a large surface area per unit volume, so most atoms exist on the surface, and it exhibits quantum confinement effects, resulting in unique electrical, magnetic, and optical properties that are different from the inherent characteristics of the material itself. , it has chemical and mechanical properties. In other words, it is possible to control various characteristics by adjusting the physical size of quantum dots (AQDs).

Quantum dots (AQDs) may be one or more types selected from the group consisting of group 2-16 quantum dots, group 13-15 quantum dots, group 14-16 quantum dots, and mixtures thereof. The group 2-16 quantum dots include binary quantum dots such as CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, and HgTe; ternary compounds such as CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe; and CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe, etc. may be selected from the group consisting of quaternary element quantum dots.

The group 13-15 quantum dots include binary quantum dots such as GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, and InSb; Tri-element compounds such as GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, and GaAlNP; and quaternary quantum dots such as GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, and InAlPSb.

The group 14-16 quantum dots include binary quantum dots such as SnS, SnSe, SnTe, PbS, PbSe, and PbTe; Tri-element compounds such as SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, and SnPbTe; and can be selected from the group consisting of quaternary element quantum dots such as SnPbSSe, SnPbSeTe, and SnPbSTe.

Quantum dots (AQDs) have the property of emitting light in a specific wavelength range depending on their size and have the property of improving color purity. Using the characteristics of these quantum dots (AQDs) of the present invention, energy is received from the light emitted from the organic light-emitting diode (OLED) and converted by the color filter (CF), and the light in a specific wavelength range is emitted to produce red, green, or blue light. Improves color purity and improves color reproducibility.

Referring to Figure 6, the quantum dot (AQD) of the present invention is arranged to overlap at least one of the red color filter (R), green color filter (G), or blue color filter (B). Quantum dots (AQDs) must be placed in an area where red, green, and blue light to improve color purity is emitted. That is, in an organic light emitting display device, the area where the red color filter (R), green color filter (G), and blue color filter (B) are placed corresponds to the area where red, green, and blue light is emitted, so the red color filter ( R), green color filter (G), or blue color filter (B), and is arranged to overlap at least one of red, green, or blue light to improve color purity and improve color reproducibility.

For example, referring to Figure 7, when PbTe quantum dots are heat treated at 340 degrees for about 15 minutes, they absorb light in the wavelength range of about 800 nm and emit red light in the same wavelength range. Therefore, light with improved color purity can be obtained.

Using this, referring again to FIG. 6, if quantum dots (AQDs) with the characteristics of FIG. 7 are included in the area of the second substrate (SUB2) overlapping with the red color filter (R), the color purity of red light can be improved. And, the color reproducibility of the organic light emitting display device can be improved.

Additionally, the quantum dots (AQDs) of the present invention may be included in the entire second substrate (SUB2). Quantum dots (AQDs) must be activated by applying thermal energy to absorb and emit light in a specific wavelength range. In the present invention, quantum dots (AQDs) are included throughout the second substrate (SUB2), and an area from which desired light is emitted, that is, at least one of a red color filter (R), a green color filter (G), or a blue color filter (B) Quantum dots (AQDs) can be activated by applying heat energy only to the overlapping area. Therefore, color reproducibility can be improved by improving the color purity of at least one of red, green, or blue light.

Meanwhile, the organic light emitting display device according to the first embodiment of the present invention may be an organic light emitting display device with a bottom emitting structure that emits light from the back. The description of the same configuration as in FIGS. 5 and 6 described above will be omitted.

Referring to FIG. 8, when light from the organic light emitting diode (OLED) is emitted to the first substrate (SUB1), a reflective layer is not provided below the first electrode (ANO), so that the light is emitted downward. And the color filter (CF) is disposed between the passivation film (PAS) and the overcoat layer (OC), so that white light emitted from the organic light emitting diode (OLED) is converted in the color filter (CF). Additionally, the UV absorption layer (UVL) is disposed between the first substrate (SUB1) and the organic light emitting diode (OLED) to block the UV laser from reaching the light emitting layer (EML) of the organic light emitting diode (OLED). For example, the UV absorption layer (UVL) is disposed between the first substrate (SUB1) and the first buffer layer (BUF1) to overlap the path through which light from the organic light emitting diode (OLED) is emitted, that is, the color filter (CF). However, the UV absorption layer (UVL) may be located anywhere between the first substrate (SUB1) and the organic light emitting diode (OLED).

Referring to FIG. 9, the quantum dot (AQD) of the present invention is included in the first substrate (SUB1). Quantum dots (AQDs) are arranged to overlap at least one of the red color filter (R), green color filter (G), or blue color filter (B), improving color purity of at least one of red, green, or blue light to improve color reproducibility. improves Additionally, the quantum dots (AQDs) of the present invention may be included in the entire first substrate (SUB2).

The organic light emitting display device according to the first embodiment of the present invention described above may include quantum dots in a glass substrate such as the first or second substrate in the following manner.

Referring to FIG. 10, quantum dots may be implanted into a glass substrate (SUB) using ion implantation. First, prepare positive ions (QDI+) and negative ions (QDI-) that make up quantum dots. For example, for PbS quantum dots, prepare Pb4+ cations and S4- anions. Then, quantum dot positive ions (QDI+) and negative ions (QDI-) are injected into a certain area of the glass substrate (SUB) using plasma ion implantation. The ion implantation device uses a known ion implantation device.

Then, a UV laser is irradiated to apply thermal energy to the desired area of the glass substrate (SUB) implanted with quantum dot positive ions (QDI+) and negative ions (QDI-). The UV laser may be, for example, a Nd:YAG laser. When high heat from the laser is applied, quantum dot positive ions (QDI+) and negative ions (QDI-) form ionic bonds with each other to form quantum dots (AQD). By further irradiating the formed quantum dots (AQDs) with a UV laser, the properties can be adjusted by adjusting the size of the quantum dots (AQDs).

As described above, the organic light emitting display device according to the first embodiment of the present invention forms quantum dots in a substrate from which light is emitted, thereby improving the color purity of a specific color without providing a separate quantum dot layer, thereby improving the color reproduction rate. There are benefits to this.

<Second Embodiment>

FIG. 12 is a cross-sectional view schematically showing an organic light-emitting display device according to a second embodiment of the present invention, and FIG. 13 is a cross-sectional view of a subpixel area of an organic light-emitting display device according to another second embodiment of the present invention. Figure 14 is an image of quantum dots, and Figure 15 is a graph showing the radius of quantum dots according to heat treatment time. In the following, the description of the same configuration as the first embodiment described above will be omitted or simplified.

The organic light emitting display device according to the second embodiment of the present invention includes quantum dots (AQDs) in the first substrate (SUB1) or the second substrate (SUB2).

Referring to FIG. 12, in the case of an organic light emitting display device with a top emission structure in which light from an organic light emitting diode (OLED) is emitted to a second substrate SUB2, quantum dots (AQDs) are included in the second substrate SUB2. In addition, referring to FIG. 13, in the case of an organic light emitting display device with a bottom emitting structure in which light from an organic light emitting diode (OLED) is emitted to a first substrate (SUB1), quantum dots (AQDs) are included in the first substrate (SUB1). .

In the second embodiment of the present invention, quantum dots (AQD) are included in the entire first substrate (SUB1) or second substrate (SUB2), and may be divided into active quantum dots (QD1) and inactive quantum dots (QD2). Active quantum dots (QD1) are quantum dots that have the characteristic of absorbing and emitting light in a specific wavelength range when thermal energy, that is, a UV laser, is irradiated to the quantum dot. Inactive quantum dots (QD2) are quantum dots that do not have light absorption or emission characteristics because thermal energy is not applied to the quantum dots.

In the second embodiment of the present invention, the inactive quantum dots (QD2) are formed on the entire first substrate (SUB1) or the second substrate (SUB2), but the active quantum dots (QD1) can be formed by irradiating a UV laser only to the desired area. . For example, in the inactive quantum dots (QD2) of the first substrate (SUB1) or the second substrate (SUB2) overlapping with at least one of the red color filter (R), green color filter (G), or blue color filter (B). By irradiating a UV laser to form active quantum dots (QD1), the color purity of at least one of red, green, or blue light is improved, thereby improving color reproducibility.

The first or second substrate according to the second embodiment of the present invention described above can include quantum dots in the first or second substrate by manufacturing a glass substrate by mixing quantum dots when manufacturing a glass substrate.

Specifically, a method of manufacturing a glass substrate can be used by mixing quantum dots, that is, inactive quantum dots, with a glass composition. For example, when melting a glass system (GeO ₂ -Li ₂ O-ZnO), a certain amount of PbS quantum dots can be melted together, and then the melt can be filled into a mold to manufacture a glass substrate. The glass substrate manufactured in this way may contain inactive quantum dots dispersed inside. By irradiating a UV laser to the inactive quantum dots included in the manufactured glass substrate, they can be formed into active quantum dots.

Referring to FIG. 14, when a glass substrate containing inactive quantum dots is heat treated at 400 degrees for 15 minutes, quantum dots with an average size of 6.5 nm are manufactured. Additionally, referring to Figure 15, as the heat treatment time increases, the radius of the quantum dots increases.

Based on these results, it can be confirmed that it is possible to manufacture quantum dots with desired properties by adjusting the heat treatment time.

As described above, the organic light emitting display device according to the second embodiment of the present invention forms quantum dots in a substrate from which light is emitted, thereby improving color purity of a specific color without providing a separate quantum dot layer, thereby improving color reproduction rate. There are benefits to this.

Through the above-described content, those skilled in the art will be able to see that various changes and modifications can be made without departing from the technical idea of the present invention. Therefore, the technical scope of the present invention should not be limited to what is described in the detailed description of the specification, but should be defined by the scope of the patent claims.

TFT: thin film transistor SUB1: first substrate
OLED: Organic light emitting diode SUB2: Second substrate
UVL: UV absorbing layer AQD: Quantum dots

Claims (18)

A thin film transistor located on a first substrate;
an organic light emitting diode connected to the thin film transistor;
a second substrate that seals the organic light emitting diode and faces the first substrate;
a plurality of quantum dots included in the first substrate or the second substrate disposed in a direction in which light is emitted from the organic light emitting diode; and
A UV absorption layer disposed between the organic light emitting diode and a substrate including the plurality of quantum dots among the first substrate and the second substrate.
A display device including a. According to claim 1,
A display device wherein light from the organic light emitting diode is emitted to the first substrate, and the plurality of quantum dots are included in the first substrate. According to clause 2,
A display device further comprising a color filter disposed between the organic light emitting diode and the first substrate. According to clause 3,
The color filter includes at least one of red, green, blue, and white color filters,
A display device wherein the plurality of quantum dots overlap with at least one of the red, green, blue, and white color filters. According to clause 4,
A display device wherein the plurality of quantum dots are included throughout the first substrate. According to clause 5,
A display device wherein the plurality of quantum dots include active quantum dots and inactive quantum dots. According to clause 2,
The UV absorption layer is disposed between the organic light emitting diode and the first substrate. According to claim 1,
A display device wherein light from the organic light emitting diode is emitted to the second substrate, and the plurality of quantum dots are included in the second substrate. According to clause 8,
A display device further comprising a color filter disposed between the organic light emitting diode and the second substrate. According to clause 9,
The color filter includes at least one of red, green, blue, and white color filters,
A display device wherein the plurality of quantum dots overlap with at least one of the red, green, blue, and white color filters. According to claim 10,
A display device wherein the plurality of quantum dots are included throughout the second substrate. According to claim 11,
A display device wherein the plurality of quantum dots include active quantum dots and inactive quantum dots. According to clause 8,
The UV absorption layer is disposed between the organic light emitting diode and the second substrate. A thin film transistor located on a first substrate;
an organic light emitting diode connected to the thin film transistor;
a second substrate that seals the organic light emitting diode and faces the first substrate;
A plurality of quantum dots included in the first substrate or the second substrate are disposed in a direction in which light is emitted from the organic light emitting diode,
A display device wherein the plurality of quantum dots include active quantum dots and inactive quantum dots. According to claim 14,
The display device further includes a UV absorption layer disposed between the organic light emitting diode and a substrate including the plurality of quantum dots among the first substrate and the second substrate. According to claim 14,
The display device further includes a color filter disposed between the organic light emitting diode and a substrate including the plurality of quantum dots among the first substrate and the second substrate. According to claim 16,
The color filter includes at least one of a red color filter, a green color filter, and a blue color filter,
The display device wherein the plurality of quantum dots overlap with at least one of the red color filter, the green color filter, and the blue color filter. The method of claim 1 or 15,
The UV absorption layer is a display device made of a benzophenone-based compound, a benzotriazole-based compound, a salicylic acid-based compound, an acrylonitrile-based compound, a free nickel compound, or a monobenzoic acid-based compound.

Images