Display device and display panel

Abstract

The invention relates to the technical field of display, and particularly provides a display device and a display panel. The display device of the present invention comprises: an anode; a cathode; the N light-emitting units are arranged between the anode and the cathode in a stacked mode, the nth light-emitting unit comprises an organic material light-emitting layer or a quantum dot light-emitting layer, n is larger than or equal to 1 and smaller than or equal to N, N is a natural number larger than or equal to 2, and the light-emitting layers of the N light-emitting units are not completely the same; a hole barrier layer, a charge generation layer and a hole transport layer are sequentially stacked between every two adjacent light-emitting units in the direction away from the anode, the anode and the cathode form a micro-cavity with resonant wavelength, and the light-emitting layers are arranged at different antinode positions of the resonant wavelength resonating in the micro-cavity. The overall visual angle brightness of the display device can be improved, and the color gamut performance can be improved.

Description

Technical Field

[0001] This invention relates to the field of display technology, and specifically provides a display device and a display panel. Background Technology

[0002] OLED, with its superior display performance, has distinguished itself in the current mobile terminal display field, becoming a highly favored "new darling." Meanwhile, with the rise of emerging concepts such as the metaverse, the demand for display performance is increasing daily. Smart hardware devices urgently need higher brightness to address the problem of contrast degradation in sunlight, while also requiring lower power consumption to achieve longer battery life and alleviate the widespread "battery anxiety" of modern people. Furthermore, a longer lifespan is crucial for ensuring a good reputation among users and for after-sales service. Therefore, high brightness, high efficiency, and long lifespan have become the main directions of OLED research in recent years. However, due to the structural limitations of organic light-emitting display devices, efficiency characteristics are restricted, and the current increases. This increases the electrical and thermal stress on the device, leading to reduced device reliability. To solve these problems, researchers have developed dual-emitting-layer OLED display devices, significantly improving device lifespan, efficiency, and peak brightness.

[0003] After achieving the same peak brightness, current research focus on OLED displays is gradually shifting from high efficiency and high brightness to high color gamut and wide viewing angle. As the color gamut of display devices improves, they can present richer colors. A deeper color gamut not only makes real-world images closer to the full colors of nature, resulting in richer and more vibrant displays, but also effectively reduces eye strain. This means that after using electronic devices for the same amount of time, display devices with richer colors are more eye-friendly. Therefore, researchers have been increasing their investment in deep color gamut research in recent years, and color gamut standards have also been gradually improved, from meeting DCI-P3 to using the BT.2020 color gamut for evaluation. Therefore, improving the color gamut of future display devices will become a key research focus. Currently, due to the spectral limitations of luminescent materials, phosphorescent and fluorescent materials cannot achieve a sufficiently large color gamut while ensuring efficiency. Therefore, researchers are developing TADF-related materials to gradually improve the color gamut while minimizing efficiency loss, but this will still require a considerable amount of time to develop luminescent materials. In the dark gamut, quantum dots possess unique advantages due to their excellent spectral designability. Because the spectrum of quantum dots can be designed to be extremely narrow, their color purity is higher, making them more suitable for use as luminescent materials to meet future product demands in the dark gamut. Currently, the efficiency of quantum dot materials is still lower than that of conventional OLED phosphorescent or fluorescent materials. Therefore, while using quantum dots alone to fabricate display devices can significantly improve the color gamut, the high power consumption problem remains difficult to solve. Summary of the Invention

[0004] To overcome the above-mentioned defects, the present invention proposes a display device and a display panel that can improve the overall viewing angle brightness of the display device and enhance its color gamut performance.

[0005] In a first aspect, the present invention provides a display device comprising:

[0006] anode;

[0007] cathode; and

[0008] N light-emitting units are stacked between the anode and the cathode, wherein the nth light-emitting unit includes an organic material light-emitting layer or a quantum dot light-emitting layer, wherein 1≤n≤N, N is a natural number greater than or equal to 2, and the light-emitting layers of the N light-emitting units are not completely identical;

[0009] Between two adjacent light-emitting units, a hole blocking layer, a charge generating layer, and a hole transport layer are stacked sequentially in the direction away from the anode. The anode and cathode constitute a microcavity with a resonant wavelength, and each light-emitting layer is disposed at a different antinode position of the resonant wavelength in the microcavity.

[0010] Furthermore, the luminescent material of the organic material luminescent layer includes phosphorescent luminescent materials and / or fluorescent luminescent materials.

[0011] Furthermore, the first light-emitting unit among the N light-emitting units that is closest to the anode includes a quantum dot light-emitting layer.

[0012] Furthermore, the nth light-emitting unit also includes an organic light-emitting layer for adjusting the optical path from the light-emitting layer to the anode, wherein the light-emitting layer is formed on the organic light-emitting layer and the organic light-emitting layer is closer to the anode relative to the light-emitting layer.

[0013] Furthermore, the organic material light-emitting layer includes a red light material layer, a green light material layer, and a blue light material layer arranged side by side perpendicular to the light-emitting direction;

[0014] The quantum dot luminescent layer includes a red quantum dot layer, a green quantum dot layer, and a blue quantum dot layer arranged side by side perpendicular to the luminescence direction;

[0015] The red light material layer is disposed corresponding to the red light quantum dot layer, the green light material layer is disposed corresponding to the green light quantum dot layer, and the blue light material layer is disposed corresponding to the blue light quantum dot layer.

[0016] Furthermore, the peak value of the red light emitted from the red quantum dot layer is ≥636nm and the full width at half maximum (FWHM) is ≤34.3nm; the peak value of the blue light emitted from the blue quantum dot layer is 460-466nm and the FWHM is ≤16.5nm; and the peak value of the blue light emitted from the green quantum dot layer is ≤518nm and the FWHM is ≤27.3nm.

[0017] Furthermore, when N equals 2, a first light-emitting unit and a second light-emitting unit are disposed between the anode and the cathode, wherein the first light-emitting unit includes a quantum dot light-emitting layer and the second light-emitting unit includes an organic material light-emitting layer; wherein,

[0018] The optical path from the quantum dot light-emitting layer to the anode is L1, and the length of L1 is: λ1 is the wavelength of the spectral peak of the light emitted from the quantum dot luminescent layer, the error of L1 is not greater than the first preset value, and n1 is a natural number.

[0019] The optical path length from the organic light-emitting material layer to the anode is L2, and the length of L2 satisfies: λ2, where λ2 is the wavelength of the spectral peak of the light emitted from the organic light-emitting material, and the error of L2 is no greater than the second preset value; n2 is a natural number; n1≠n2;

[0020] The length of the microcavity is an integer multiple of λ² / 2.

[0021] Furthermore, the first preset value and the second preset value are 10nm.

[0022] Furthermore, the first light-emitting unit further includes a first organic light-emitting layer, wherein the quantum dot light-emitting layer is formed on the first organic light-emitting layer, and the first organic light-emitting layer is closer to the anode than the quantum dot light-emitting layer; the first organic light-emitting layer includes a first red light organic layer, a first green light organic layer, and a first blue light organic layer arranged side by side perpendicular to the light emission direction;

[0023] The first red light organic layer is disposed correspondingly to the red light quantum dot layer to adjust the optical path from the red light quantum dot layer to the anode;

[0024] The first green organic layer is disposed correspondingly to the green quantum dot layer to adjust the optical path from the green quantum dot layer to the anode;

[0025] The first blue light organic layer is disposed correspondingly to the blue light quantum dot layer to adjust the optical path from the blue light quantum dot layer to the anode.

[0026] Furthermore, the second light-emitting unit also includes a second organic light-emitting layer, wherein the organic material light-emitting layer is formed on the second organic light-emitting layer, and the second organic light-emitting layer is closer to the anode relative to the organic material light-emitting layer; the second organic light-emitting layer includes a second red light organic layer, a second green light organic layer and a second blue light organic layer arranged side by side perpendicular to the light emission direction;

[0027] The second red light organic layer is disposed correspondingly to the red light material layer to adjust the optical path from the red light material layer to the anode;

[0028] The second green light organic layer is disposed correspondingly to the green light material layer to adjust the optical path from the green light material layer to the anode;

[0029] The second blue light organic layer is disposed correspondingly to the blue light material layer to adjust the optical path from the blue light material layer to the anode.

[0030] Furthermore, the charge generation layer includes an N-type charge generation layer and a P-type charge generation layer stacked sequentially from the anode toward the cathode.

[0031] Furthermore, the device also includes:

[0032] A hole injection layer is formed on the anode;

[0033] A first hole transport layer is formed on the hole injection layer; wherein, the first light-emitting unit is formed on the first hole transport layer;

[0034] The nth hole blocking layer is formed on the nth light-emitting unit;

[0035] An electron transport layer is formed on the nth hole blocking layer;

[0036] A Yb layer is formed on the electron transport layer; wherein,

[0037] The cathode is formed on the Yb layer.

[0038] Furthermore, the device also includes:

[0039] An encapsulation layer is formed on the cathode.

[0040] In a second aspect, the present invention provides a display panel, comprising:

[0041] Substrate;

[0042] The display device described in the first aspect is formed in an array arrangement on the substrate.

[0043] Furthermore, the display panel also includes a color filter layer, wherein the color filter layer includes a red color filter, a green color filter, a blue color filter, and a black matrix separating the various color filters.

[0044] Furthermore, the difference between the wavelengths of the spectral peaks of the light emitted through the green and blue color resists and the wavelength λ3 of the spectral peak of the light emitted by the display device is ≤10nm.

[0045] Furthermore, the display panel also includes a polarizer.

[0046] The above-described technical solutions of the present invention have at least one or more of the following beneficial effects:

[0047] In implementing the technical solution of this invention, the display device includes both an organic material light-emitting layer and a quantum dot light-emitting layer, fully utilizing the high efficiency characteristics of existing OLED materials and the unique advantages of quantum dots, namely their high color gamut and wide viewing angle characteristics. By placing the two light-emitting layers in specific positions, the final fabricated display device not only achieves a significant improvement in efficiency but also reaches a higher level in color gamut performance, thereby providing users with a superior visual experience. Attached Figure Description

[0048] The disclosure of this invention will become more readily understood with reference to the accompanying drawings. It will be readily understood by those skilled in the art that these drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention. Furthermore, similar numbers in the drawings are used to denote similar components, wherein:

[0049] Figure 1 This is a schematic block diagram of the main structure of a display device according to an embodiment of the present invention;

[0050] Figure 2 This is a schematic diagram of the device viewing angle attenuation WL-Decay according to embodiments and comparative examples of the present invention;

[0051] Figure 3 This is a schematic diagram of the CIE color coordinate simulation of a Green device according to an embodiment and comparative example of the present invention.

[0052] List of reference numerals :

[0053] 1. Anode; 2. Cathode; 3. Hole blocking layer; 4-1. N-type charge generation layer; 4-2. P-type charge generation layer; 5. Hole transport layer; 6-1. Red light material layer; 6-2. Green light material layer; 6-3. Blue light material layer; 7-1. Red light quantum dot layer; 7-2. Green light quantum dot layer; 7-3. Blue light quantum dot layer; 8-1. First red light organic layer; 8-2. First green light organic layer; 8-3. First blue light organic layer; 9-1. Second red light organic layer; 9-2. Second green light organic layer; 9-3. Second blue light organic layer; 10. Hole injection layer; 11. First hole transport layer; 12. nth hole blocking layer; 13. Electron transport layer; 14. Yb layer. Detailed Implementation

[0054] Some embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0055] Reference Figure 1 The present invention provides a display device, comprising:

[0056] Anode 1;

[0057] Cathode 2; and

[0058] N light-emitting units are stacked between the anode and the cathode, wherein the nth light-emitting unit includes an organic material light-emitting layer or a quantum dot light-emitting layer, wherein 1≤n≤N, and N is a natural number greater than or equal to 2; the light-emitting layers of the N light-emitting units are not completely identical.

[0059] Between two adjacent light-emitting units, a hole blocking layer 3, a charge generating layer, and a hole transport layer 5 are stacked sequentially in the direction away from the anode. The anode 1 and the cathode 2 constitute a microcavity with a resonant wavelength. Each light-emitting layer is disposed at a different antinode position of the resonant wavelength in the microcavity.

[0060] This invention utilizes both organic material light-emitting layers and quantum dot light-emitting layers in its display device. It fully leverages the high efficiency of existing OLED materials and the unique advantages of quantum dots, namely their high color gamut and wide viewing angle. This ingenious combination results in a display device that not only significantly improves efficiency but also achieves a higher level of color gamut performance. Specifically, this design enables brighter, clearer, and more colorful display effects, providing users with a superior visual experience. This technology has broad application prospects, not only applicable to high-end display devices such as televisions, monitors, and smartphone screens, but also potentially playing a significant role in fields such as virtual reality and augmented reality.

[0061] In one embodiment, the luminescent material of the organic material luminescent layer includes phosphorescent and / or fluorescent luminescent materials. Alternatively, TADF (Temperature-Alder Flytekt) fluorescent luminescent materials and other types of luminescent materials can be used. This invention does not impose fixed requirements on the type of luminescent material; the material type can be changed to meet different needs such as high color gamut or high efficiency.

[0062] This invention does not impose requirements on the emission spectrum of the organic material light-emitting layer. The emission spectrum of the organic material light-emitting layer can be adjusted according to the requirements of color gamut and efficiency changes to achieve the required color gamut specifications.

[0063] In one embodiment, the first light-emitting unit closest to the anode among the N light-emitting units includes a quantum dot light-emitting layer.

[0064] In a resonant cavity composed of an anode and a cathode, the light-emitting layer at the antinode position closest to the anode experiences relatively greater power generation efficiency loss because it is more affected by the SPP of the anode. Therefore, placing the slightly less efficient QD light-emitting layer closer to the anode side has less impact on device efficiency, thereby utilizing the good viewing angle characteristics of QD particles to improve the overall viewing angle brightness of the device.

[0065] In one embodiment, the nth light-emitting unit further includes an organic light-emitting layer for adjusting the optical path of the light-emitting layer to the anode, wherein the light-emitting layer is formed on the organic light-emitting layer and the organic light-emitting layer is closer to the anode relative to the light-emitting layer.

[0066] To ensure that each light-emitting layer is positioned at an antinode in the resonant cavity for optimal luminous performance, precise control over the light-emitting position can be achieved by finely adjusting the deposition thickness of the organic light-emitting layer. This method optimizes the position of each light-emitting unit within the resonant cavity, significantly improving the overall luminous performance of the display device.

[0067] In one embodiment, the organic material light-emitting layer includes a red light material layer 6-1, a green light material layer 6-2, and a blue light material layer 6-3 arranged side by side perpendicular to the light emission direction.

[0068] The quantum dot luminescent layer includes a red quantum dot layer 7-1, a green quantum dot layer 7-2, and a blue quantum dot layer 7-3 arranged side by side perpendicular to the luminescence direction.

[0069] The red light material layer 6-1 is disposed corresponding to the red light quantum dot layer 7-1, the green light material layer 6-2 is disposed corresponding to the green light quantum dot layer 7-2, and the blue light material layer 6-3 is disposed corresponding to the blue light quantum dot layer 7-3.

[0070] In one embodiment, the FWHM and material spectral peak of the quantum dot light-emitting layer are defined to achieve a display requirement of over 98% for BT.2020 Coverage, specifically as follows:

[0071] The peak value of the red light emitted from the red quantum dot layer is ≥636nm and the full width at half maximum (FWHM) is ≤34.3nm; the peak value of the blue light emitted from the blue quantum dot layer is 460-466nm and the FWHM is ≤16.5nm; the peak value of the blue light emitted from the green quantum dot layer is ≤518nm and the FWHM is ≤27.3nm.

[0072] When the emission spectrum of quantum dot (QD) particles meets the above numerical range, the color gamut of the device structure of the present invention can achieve BT.2020 Coverage ≥ 98%.

[0073] In this invention, the positions of the quantum dot light-emitting layer and the organic light-emitting material layer can be interchanged. At the same time, the positions of the R / G / B quantum dot light-emitting layer and the R / G / B organic light-emitting material layer do not have to be at the same horizontal height. That is, the light-emitting units of R / G / B near the anode side can use a mixture of QD and organic light-emitting materials, and the number and ratio can also be changed. It is only necessary to ensure that there is one QD light-emitting unit and one organic light-emitting material light-emitting unit in the same pixel.

[0074] This invention does not impose strict requirements on the emission spectrum of the organic light-emitting material layer. The emission spectrum of the organic light-emitting material layer can be adjusted according to the requirements of color gamut and efficiency changes to achieve the required color gamut specifications.

[0075] In one embodiment, a display device with differentiated upper and lower light-emitting units is fabricated by utilizing the high efficiency of existing OLED materials and the wide color gamut and wide viewing angle characteristics of quantum dots. In this invention, the two light-emitting units of the Tandem display device are fabricated using electroluminescent quantum dots and OLED light-emitting materials, respectively. The positions of the two light-emitting units can be interchanged to create a display device with higher efficiency or a wider color gamut. The following description continues... Figure 1 The design of a quantum dot light-emitting layer closer to the anode will be explained in detail as an example.

[0076] When N equals 2, this embodiment of the invention designs the light-emitting layer in the device differently, using a combination of quantum dot materials and conventional OLED light-emitting materials (phosphorescent or fluorescent materials) as different light-emitting layers. Specifically, a first light-emitting unit and a second light-emitting unit are disposed between the anode and the cathode, wherein the first light-emitting unit includes a quantum dot light-emitting layer and the second light-emitting unit includes an organic material light-emitting layer; wherein the quantum dot light-emitting layer is disposed near the anode, and its position must meet the following conditions:

[0077] The optical path from the quantum dot light-emitting layer to the anode is L1, and the length of L1 is: λ1 is the wavelength of the spectral peak of the light emitted from the quantum dot luminescent layer, the error of L1 is not greater than the first preset value, and n1 is a natural number.

[0078] The organic light-emitting material layer is disposed away from the anode, and its light-emitting position L2 and the cavity length L of the entire device need to meet the following conditions:

[0079] The optical path length from the organic light-emitting material layer to the anode is L2, and the length of L2 satisfies: λ2, where λ2 is the wavelength of the spectral peak of the light emitted from the organic light-emitting material, and the error of L2 is no greater than the second preset value; n2 is a natural number; n1≠n2;

[0080] The length of the microcavity is an integer multiple of λ² / 2.

[0081] In one embodiment, the first and second preset values ​​are both 10nm. Due to manufacturing errors,

[0082] The optical path from the quantum dot light-emitting layer to the anode in this invention is not limited to... 10nm, as long as it meets the requirements Furthermore, the R / G / B ratios can be customized to meet specific requirements. Similarly, the optical path from the organic material's light-emitting layer to the anode is not limited to... As long as it meets the requirements Furthermore, R / G / B settings can be customized according to requirements.

[0083] When the two light-emitting layers meet the above thickness requirements, the overall optical performance of the device is optimized. This is mainly because the efficiency of the tandem device is more affected by the light-emitting layer farther from the anode. Therefore, it is necessary to place the more efficient organic light-emitting material layer at the light-emitting position far from the anode to ensure the overall efficiency level of the device. The light-emitting layer closer to the anode is more affected by the SPP of the anode. Therefore, the slightly less efficient quantum dot (QD) light-emitting layer is placed closer to the anode side. By utilizing the principle that the first light-emitting unit has little impact on the device efficiency, the good viewing angle characteristics of QD particles are used to improve the overall viewing angle brightness of the device.

[0084] In one embodiment, the first light-emitting unit further includes a first organic light-emitting layer, wherein the quantum dot light-emitting layer is formed on the first organic light-emitting layer, and the first organic light-emitting layer is closer to the anode than the quantum dot light-emitting layer; the first organic light-emitting layer includes a first red light organic layer 8-1, a first green light organic layer 8-2, and a first blue light organic layer 8-3 arranged side by side perpendicular to the light emission direction;

[0085] The first red light organic layer 8-1 is correspondingly disposed to the red light quantum dot layer 7-1 to adjust the optical path from the red light quantum dot layer 7-1 to the anode 2;

[0086] The first green organic layer 8-2 is correspondingly disposed to the green quantum dot layer 7-2 to adjust the optical path from the green quantum dot layer 7-2 to the anode 2;

[0087] The first blue light organic layer 8-3 is configured to correspond with the blue light quantum dot layer 7-3 to adjust the optical path from the blue light quantum dot layer 7-3 to the anode 2.

[0088] In one embodiment, the second light-emitting unit further includes a second organic light-emitting layer, wherein the organic material light-emitting layer is formed on the second organic light-emitting layer, and the second organic light-emitting layer is closer to the anode than the organic material light-emitting layer; the second organic light-emitting layer includes a second red light organic layer 9-1, a second green light organic layer 9-2, and a second blue light organic layer 9-3 arranged side by side perpendicular to the light emission direction;

[0089] The second red light organic layer 9-1 is disposed correspondingly to the red light material layer 6-1 to adjust the optical path from the red light material layer 6-1 to the anode 2;

[0090] The second green light organic layer 9-2 is disposed correspondingly to the green light material layer 6-2 to adjust the optical path from the green light material layer 6-2 to the anode 2;

[0091] The second blue light organic layer 9-3 is disposed correspondingly to the blue light material layer 6-3 to adjust the optical path from the blue light material layer 6-3 to the anode 2.

[0092] In one embodiment, the charge generation layer includes an N-type charge generation layer 4-1 and a P-type charge generation layer 4-2 stacked sequentially from the anode toward the cathode.

[0093] In one embodiment, the device further includes:

[0094] Hole injection layer 10 is formed on the anode 2;

[0095] A first hole transport layer 11 is formed on the hole injection layer 10; wherein, a first light-emitting unit is formed on the first hole transport layer 11;

[0096] The nth hole blocking layer 12 is formed on the nth light-emitting unit.

[0097] An electron transport layer 13 is formed on the nth hole blocking layer 12;

[0098] A Yb layer 14 is formed on the electron transport layer 13; wherein,

[0099] The cathode 1 is formed on the Yb layer 14.

[0100] In one embodiment, the device further includes:

[0101] An encapsulation layer 15 is formed on the cathode 1.

[0102] In this invention, the first hole transport layer 11 and the hole transport layer 5 can be made of the same material or different materials. The hole blocking layer 3 and the nth hole blocking layer 12 can be made of the same material or different materials. This is mainly because the energy levels of the luminescent material in the organic material luminescent layer differ from those of the QD quantum dot material, thus resulting in different energy level requirements for their common layer materials. Furthermore, the luminescent units closer to the anode are more prone to SPP losses, therefore a low-refractive-index material is needed to increase the distance between the luminescent layer and the anode. Therefore, the first hole transport layer 11 and the hole transport layer 5 can be made of the same material or different materials, while the hole blocking layer 3 and the nth hole blocking layer 12 can be designed with differentiated materials.

[0103] Experimental Example 1

[0104] Still refer to Figure 1 Hole injection layer 10 (HIL) is formed on cathode 2 (AND) by vapor deposition process;

[0105] A first hole transport layer 11 (HTL1) is formed on the hole injection layer 10 (HIL);

[0106] A first red light organic layer 8-1 (B Prime1), a first green light organic layer 8-2 (G Prime1), and a first blue light organic layer 8-3 (R Prime1) are formed side by side on the first hole transport layer 11 (HTL1) by mask evaporation.

[0107] A red quantum dot layer 7-1 (R QD) is formed on the first red organic layer 8-1 (B Prime1), a green quantum dot layer 7-2 (G QD) is formed on the first green organic layer 8-2 (G Prime1), and a blue quantum dot layer 7-3 (R QD) is formed on the first blue organic layer 8-3 (R Prime1).

[0108] Continuing with the vapor deposition process, hole blocking layer 3 (HBL1) is formed on red quantum dot layer 7-1 (R QD), green quantum dot layer 7-2 (G QD) and blue quantum dot layer 7-3 (R QD).

[0109] An N-type charge generation layer 4-1 (NCGL) is formed on the hole blocking layer 3 (HBL1).

[0110] A P-type charge generation layer 4-2 (PCGL) is formed on the N-type charge generation layer 4-1 (NCGL).

[0111] A hole transport layer 5 (HTL2) is formed on the P-type charge generation layer 4-2 (PCGL).

[0112] A second red organic layer 9-1 (R Prime2), a second green organic layer 9-2 (G Prime2), and a second blue organic layer 9-3 (B Prime2) are formed side by side on the hole transport layer 5 (HTL2) by mask evaporation.

[0113] A red light material layer 6-1 (R Dopant) is formed on the second red light organic layer 9-1 (R Prime2).

[0114] A green light material layer 6-2 (G Dopant) is formed on the second green light organic layer 9-2 (G Prime2).

[0115] A blue light material layer 6-3 (B Dopant) is formed on the second blue light organic layer 9-3 (B Prime2).

[0116] Continuing with the vapor deposition process, the nth hole blocking layer 12 (HBL2) is formed on the red light material layer 6-1 (R Dopant), the green light material layer 6-2 (G Dopant), and the blue light material layer 6-3 (B Dopant).

[0117] An electron transport layer 13 (ETL) is formed on the nth hole blocking layer 12 (HBL2).

[0118] A Yb layer 14 is formed on the electron transport layer 13 (ETL). The Yb layer 14 comprises Yb.

[0119] A cathode 15 is formed on the Yb layer 14, the cathode 15 comprising Mg and Ag.

[0120] An encapsulation layer 15 (CPL) is formed on the cathode 1.

[0121] In this embodiment, the red, green, and blue quantum dot layers (7-1 to 7-3) and the red, green, and blue material layers (6-1 to 6-3) are located at different antinodes of the resonant cavity formed by the cathode 1 and the anode 2, respectively, specifically at 1 / 2 period.

[0122] Comparative Example 1

[0123] The red quantum dot layer 7-1 (R QD), green quantum dot layer 7-2 (G QD), and blue quantum dot layer 7-3 (R QD) in Example 1 were all replaced with conventional fluorescent light-emitting material layers.

[0124] Comparative Example 2

[0125] The red light material layer 6-1 (R Dopant), green light material layer 6-2 (G Dopant), and blue light material layer 6-3 (B Dopant) in Example 1 are all replaced with quantum dot light-emitting material layers.

[0126] The device performance of Example 1, Comparative Example 1, and Comparative Example 2 was tested through simulation. The simulation results are as follows: Figure 2 As shown, from Figure 2 The WL-Decay relationship shows that using QD particles as one of the emitting units in the dual emitting layer significantly slows down the viewing angle brightness decay of the device. Using QD as the emitting material also significantly increases the color gamut of the device, such as... Figure 3 This is mainly because after using QD particles as the light-emitting material, the final light emission spectrum of the device will be significantly narrowed due to the influence of the QD particle emission spectrum. This is mainly because FWHMQD (Comparative Example 2) < FWHMDevice (Example 1) < FWHMDopant (Comparative Example 1). The final light emission spectrum of the device is the combined light emission spectrum of the quantum dot QD light-emitting layer and the organic material light-emitting Dopant layer.

[0127] Because the light-emitting characteristics of QD particles are closer to the intensity distribution of a Lamborgh light source (intensity remains essentially constant with increasing viewing angle), their viewing angle characteristics are significantly better than those of conventional OLED light-emitting materials. Therefore, in this invention, QD particles are placed in the first light-emitting unit to utilize their excellent viewing angle characteristics to mitigate the attenuation of viewing angle brightness in dual-layer devices. Simultaneously, the emission spectrum of QD particles is significantly narrower than that of conventional phosphorescent and fluorescent materials, resulting in higher color purity. Using one layer of QD light-emitting material and one layer of conventional device light-emitting material in a dual-layer device significantly improves the viewing angle characteristics and color gamut compared to conventional tandem devices. Conventional tandem devices typically have two light-emitting units arranged in a 1 / 2-cycle configuration. A 1-cycle light-emitting unit has weaker wide-angle interference intensity, resulting in a weaker microcavity effect and a slightly inferior color gamut compared to a single-layer device.

[0128] This invention introduces electroluminescent quantum dots into the emissive layer of a dual-emissive-layer or multi-emissive-layer OLED device structure and differentiates the upper and lower emissive units of the tandem structure to design a novel OLED tandem device structure (fluorescent-QD, phosphorescent-QD, TADF-QD combination) with high color gamut, high efficiency, and wide viewing angle. Simultaneously, through quantum dot spectral design and special design of the upper and lower emissive units of the dual-layer OLED device, the color gamut, viewing angle, and efficiency of the tandem OLED are improved.

[0129] The present invention also provides a display panel, comprising:

[0130] Substrate;

[0131] The display device formed in an array on the substrate.

[0132] The display panel further includes a polarizer. The display device of this invention can be applied not only to POL-structured display devices but also to COE display devices. Therefore, the display panel may further include a color filter layer, wherein the color filter layer includes red color resist, green color resist, blue color resist, and a black matrix separating the various color resists. The color gamut and efficiency of the display device are further improved through the POL-Less structure and the filtering effect of the color filter, thus significantly improving display performance. Therefore, when the color filter layer is combined in the display device of this invention, the spectrum of the color filter is limited as follows:

[0133] The difference between the wavelengths of the spectral peaks of the light emitted through the green and blue color filters and the wavelength λ3 of the spectral peak of the light emitted from the display device is ≤10nm. Limiting the difference between the color filter's spectral peak value and the device's spectral peak value is primarily to ensure a greater performance improvement for the device after using a color filter.

[0134] This invention provides a deep gamut, wide viewing angle, and high efficiency OLED display device. The device structure is applicable to any OLED display device with multiple light-emitting units. Through specific design, differentiated dual-emitting-layer or multi-emitting-layer designs are used and positioned at different locations within the device to achieve the desired optical performance, including a deep gamut and wide viewing angle, thus resulting in superior display performance.

[0135] It should be noted that although the steps in the above embodiments are described in a specific order, those skilled in the art will understand that in order to achieve the effects of the present invention, different steps do not necessarily have to be executed in such an order. They can be executed simultaneously (in parallel) or in other orders, and these variations are all within the scope of protection of the present invention.

[0136] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A display device, characterized in that, include: anode; cathode; as well as N light-emitting units are stacked between the anode and the cathode, wherein the nth light-emitting unit includes an organic material light-emitting layer or a quantum dot light-emitting layer, wherein 1≤n≤N, N is a natural number greater than or equal to 2, and the light-emitting layers of the N light-emitting units are not completely identical; Between two adjacent light-emitting units, a hole blocking layer, a charge generating layer, and a hole transport layer are stacked sequentially in the direction away from the anode. The anode and cathode constitute a microcavity with a resonant wavelength, and each light-emitting layer is disposed at a different antinode position of the resonant wavelength in the microcavity.

2. The device according to claim 1, characterized in that, The luminescent materials of the organic material luminescent layer include phosphorescent materials and / or fluorescent materials.

3. The device according to claim 1, characterized in that, The first light-emitting unit among the N light-emitting units that is closest to the anode includes a quantum dot light-emitting layer.

4. The device according to claim 1, characterized in that, The nth light-emitting unit further includes an organic light-emitting layer for adjusting the optical path from the light-emitting layer to the anode, wherein the light-emitting layer is formed on the organic light-emitting layer and the organic light-emitting layer is closer to the anode relative to the light-emitting layer.

5. The device according to claim 1, characterized in that, The organic material light-emitting layer includes a red light material layer, a green light material layer, and a blue light material layer arranged side by side perpendicular to the light-emitting direction; The quantum dot luminescent layer includes a red quantum dot layer, a green quantum dot layer, and a blue quantum dot layer arranged side by side perpendicular to the luminescence direction; The red light material layer is disposed corresponding to the red light quantum dot layer, the green light material layer is disposed corresponding to the green light quantum dot layer, and the blue light material layer is disposed corresponding to the blue light quantum dot layer.

6. The device according to claim 5, characterized in that, The peak value of the red light emitted from the red quantum dot layer is ≥636nm and the full width at half maximum (FWHM) is ≤34.3nm; the peak value of the blue light emitted from the blue quantum dot layer is 460-466nm and the FWHM is ≤16.5nm; the peak value of the blue light emitted from the green quantum dot layer is ≤518nm and the FWHM is ≤27.3nm.

7. The device according to claim 5, characterized in that, When N equals 2, a first light-emitting unit and a second light-emitting unit are disposed between the anode and the cathode, wherein the first light-emitting unit includes a quantum dot light-emitting layer and the second light-emitting unit includes an organic material light-emitting layer; wherein, The optical path from the quantum dot light-emitting layer to the anode is L1, and the length of L1 is: λ1 is the wavelength of the spectral peak of the light emitted from the quantum dot luminescent layer, the error of L1 is not greater than the first preset value, and n1 is a natural number. The optical path length from the organic light-emitting material layer to the anode is L2, and the length of L2 satisfies: λ2, where λ2 is the wavelength of the spectral peak of the light emitted from the organic light-emitting material, and the error of L2 is no greater than the second preset value; n2 is a natural number; n1≠n2; The length of the microcavity is an integer multiple of λ² / 2.

8. The device according to claim 7, characterized in that, The first preset value and the second preset value are 10nm.

9. The device according to claim 7, characterized in that, The first light-emitting unit further includes a first organic light-emitting layer, wherein the quantum dot light-emitting layer is formed on the first organic light-emitting layer, and the first organic light-emitting layer is closer to the anode than the quantum dot light-emitting layer; the first organic light-emitting layer includes a first red light organic layer, a first green light organic layer and a first blue light organic layer arranged side by side perpendicular to the light emission direction; The first red light organic layer is disposed correspondingly to the red light quantum dot layer to adjust the optical path from the red light quantum dot layer to the anode; The first green organic layer is disposed correspondingly to the green quantum dot layer to adjust the optical path from the green quantum dot layer to the anode; The first blue light organic layer is disposed correspondingly to the blue light quantum dot layer to adjust the optical path from the blue light quantum dot layer to the anode.

10. The device according to claim 9, characterized in that, The second light-emitting unit further includes a second organic light-emitting layer, wherein the organic material light-emitting layer is formed on the second organic light-emitting layer, and the second organic light-emitting layer is closer to the anode than the organic material light-emitting layer; the second organic light-emitting layer includes a second red light organic layer, a second green light organic layer and a second blue light organic layer arranged side by side perpendicular to the light emission direction; The second red light organic layer is disposed correspondingly to the red light material layer to adjust the optical path from the red light material layer to the anode; The second green light organic layer is disposed correspondingly to the green light material layer to adjust the optical path from the green light material layer to the anode; The second blue light organic layer is disposed correspondingly to the blue light material layer to adjust the optical path from the blue light material layer to the anode.

11. The device according to claim 1, characterized in that, The charge generation layer includes an N-type charge generation layer and a P-type charge generation layer stacked sequentially from the anode toward the cathode.

12. The device according to claim 1, characterized in that, The device also includes: A hole injection layer is formed on the anode; A first hole transport layer is formed on the hole injection layer; wherein, the first light-emitting unit is formed on the first hole transport layer; The nth hole blocking layer is formed on the nth light-emitting unit; An electron transport layer is formed on the nth hole blocking layer; A Yb layer is formed on the electron transport layer; wherein, The cathode is formed on the Yb layer.

13. The device according to claim 12, characterized in that, The device further includes an encapsulation layer formed on the cathode.

14. A display panel, characterized in that, include: Substrate; A display device according to any one of claims 1-13, formed in an array on the substrate.

15. The display panel according to claim 14, characterized in that, The display panel further includes a color filter layer, wherein the color filter layer includes a red color filter, a green color filter, a blue color filter, and a black matrix separating the various color filters.

16. The display panel according to claim 14, characterized in that, The difference between the wavelengths of the spectral peaks of the light emitted through the green and blue color resists and the wavelength λ3 of the spectral peak of the light emitted by the display device is ≤10nm.

17. The display panel according to claim 14, characterized in that, The display panel also includes a polarizer.

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