Display panel and display device

Abstract

This invention discloses a display panel and a display device. The display panel includes a substrate and at least one light-emitting structure disposed on the substrate. The light-emitting structure includes a first light-emitting element and a color-converting light-emitting element. The first light-emitting element includes a first color light-emitting layer. The color-converting light-emitting element is stacked on the substrate along a first direction perpendicular to the substrate, and includes a second color light-emitting layer and a third color conversion layer stacked with the second color light-emitting layer along the first direction. This invention can improve the luminous efficiency of the third color in the display panel, thereby improving the brightness and display effect of the display panel.

Description

Technical Field

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

[0002] Micro LED (Micro Light-Emitting Diode) display panels are created by miniaturizing traditional LEDs to form micrometer-pitch LED arrays, achieving ultra-high density pixel resolution. Micro LED displays possess self-emissive characteristics. Compared to Organic Light-Emitting Diode (OLED) and Liquid Crystal Display (LCD) panels, Micro LED display panels offer easier and more accurate color calibration, longer lifespan, higher brightness, and advantages in thinness and energy efficiency.

[0003] Currently, in order to achieve other colors or full-color display of inorganic light-emitting diodes, it is often necessary to stack multiple inorganic light-emitting diodes together in a horizontal or vertical manner. Vertical stacking has the advantage of significantly improving PPI compared to horizontal stacking. However, since the luminous efficiency of different color light-emitting layers is different, for example, the luminous efficiency of some colors is lower than that of other colors, it will affect the brightness of the display panel and the display effect. Summary of the Invention

[0004] This invention provides a display panel and display device that can improve the luminous efficiency of a third color in the display panel, thereby improving the brightness and display effect of the display panel.

[0005] This invention also provides a display panel, the display panel including a substrate and at least one light-emitting structure disposed on the substrate, the light-emitting structure including:

[0006] The first light-emitting element includes a first color light-emitting layer;

[0007] A color-converting light-emitting element is stacked on the substrate along a first direction, wherein the first direction is perpendicular to the substrate. The color-converting light-emitting element includes a second color light-emitting layer and a third color-converting layer stacked with the second color light-emitting layer along the first direction.

[0008] In one embodiment of the present invention, the luminous efficiency of the third-color quantum well material is less than that of the second-color luminous layer, and the third-color quantum well material includes at least one of InGaN, GaN, AlGaInP, and GaInP quantum well materials.

[0009] In one embodiment of the present invention, the luminous efficiency of the third-color quantum well material is less than that of the first-color luminous layer.

[0010] In one embodiment of the present invention, the light-emitting structure further includes a second light-emitting element, which is stacked on the substrate along the first direction with the first light-emitting element and the color-converting light-emitting element. The second light-emitting element includes a fourth color light-emitting layer, and the luminous efficiency of the third color quantum well material is less than the luminous efficiency of the fourth color light-emitting layer.

[0011] In one embodiment of the present invention, the color-converting light-emitting element is disposed on the substrate, the second light-emitting element is disposed on the side of the color-converting light-emitting element away from the substrate, and the first light-emitting element is disposed on the side of the second light-emitting element away from the color-converting light-emitting element;

[0012] The luminous efficiency of the first color emitting layer is greater than that of the fourth color emitting layer.

[0013] In one embodiment of the present invention, the light-emitting structure further includes a first reflective layer disposed between the color-converting light-emitting element and the substrate, and a second Bragg reflective layer disposed between the color-converting light-emitting element and the second light-emitting element;

[0014] The first reflective layer reflects light of the second color and light of the third color, and the second Bragg reflective layer reflects light of the second color.

[0015] In one embodiment of the present invention, the first reflective layer includes a first Bragg reflective layer, the first Bragg reflective layer includes a first sub-part and a second sub-part stacked along the first direction, and the first sub-part reflects light of the second color, and the second sub-part reflects light of the third color;

[0016] The first sub-part includes a plurality of first sub-layers and a plurality of second sub-layers stacked and alternately arranged; the second sub-part includes a plurality of third sub-layers and a plurality of fourth sub-layers stacked and alternately arranged; and the second Bragg reflector layer includes a plurality of fifth sub-layers and a plurality of sixth sub-layers stacked and alternately arranged.

[0017] Wherein, the thickness of the first sub-layer and the thickness of the second sub-layer are both equal to one-quarter of the wavelength of the second color light, the thickness of the third sub-layer and the thickness of the fourth sub-layer are both equal to one-quarter of the wavelength of the third color light, and the thickness of the fifth sub-layer and the thickness of the sixth sub-layer are both equal to one-quarter of the wavelength of the second color light.

[0018] In one embodiment of the present invention, the materials of the first sublayer, the third sublayer, and the fifth sublayer all include silicon oxide, and the materials of the second sublayer, the fourth sublayer, and the sixth sublayer all include titanium oxide.

[0019] In one embodiment of the present invention, the display panel further includes at least one first electrode and a plurality of second electrodes connected to the light-emitting structure, wherein at least the first color light-emitting layer and the fourth color light-emitting layer are connected to the first electrode, and each of the first color light-emitting layer and the fourth color light-emitting layer is independently connected to one of the second electrodes.

[0020] In one embodiment of the present invention, the first reflective layer is reused as a bonding metal layer, the color conversion light-emitting element is connected to the substrate through the bonding metal layer, and the second color light-emitting layer is connected to the first electrode or to a second electrode.

[0021] In one embodiment of the present invention, the first color is blue or green, the second color is blue or green, and the third color is red.

[0022] In one embodiment of the invention, the fourth color may be the same as or different from the second color.

[0023] In one embodiment of the present invention, the material of the third color conversion layer includes quantum dot material or phosphor material.

[0024] According to the above-mentioned objectives of the present invention, embodiments of the present invention also provide a display device, the display device including the display panel.

[0025] The beneficial effects of the present invention are as follows: In the color conversion light-emitting element, a second color light-emitting layer and a third color color conversion layer are stacked. In the implementation and application process, the second color light-emitting layer with higher luminous efficiency can be selected to emit light, so as to excite the third color conversion layer to emit the third color light, thereby improving the luminous efficiency of the third color in the display panel and improving the brightness and display effect of the display panel. Attached Figure Description

[0026] The technical solution and other beneficial effects of the present invention will become apparent from the following detailed description of specific embodiments of the invention, in conjunction with the accompanying drawings.

[0027] Figure 1 A schematic diagram of a light-emitting structure provided in an embodiment of the present invention;

[0028] Figure 2 This is another schematic diagram of the light-emitting structure provided in an embodiment of the present invention;

[0029] Figure 3 This is another schematic diagram of the light-emitting structure provided in an embodiment of the present invention;

[0030] Figures 4 to 15 This is a schematic diagram illustrating the fabrication process of the light-emitting structure provided in an embodiment of the present invention. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0032] The following disclosure provides many different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this invention, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0033] This invention also provides a display panel, please refer to... Figure 1 The display panel includes a substrate 10 and at least one light-emitting structure disposed on the substrate 10. The light-emitting structure includes a first light-emitting element 20 and a color-converting light-emitting element 30.

[0034] The first light-emitting element 20 includes a first color light-emitting layer 21; the color-converting light-emitting element 30 is stacked with the first light-emitting element 20 on the substrate 10 along a first direction M, where the first direction M is perpendicular to the substrate 10. The color-converting light-emitting element 30 includes a second color light-emitting layer 31 and a third color conversion layer 32 stacked with the second color light-emitting layer 31 along the first direction M.

[0035] In the implementation and application process, in the embodiment of the present invention, a second color light-emitting layer 31 and a third color color conversion layer 32 are stacked in the color conversion light-emitting element 30. The present invention can choose to use the second color light-emitting layer 31 with higher luminous efficiency to emit light, so as to excite the third color conversion layer 32 to emit the third color light, thereby improving the luminous efficiency of the third color in the display panel and improving the brightness and display effect of the display panel.

[0036] Specifically, in one embodiment of the present invention, please continue to refer to... Figure 1 The display panel includes a substrate 10 and a plurality of light-emitting structures disposed on the substrate 10, and Figure 1 The following description will take one of the light-emitting structures disposed on the substrate 10 as an example.

[0037] The light-emitting structure includes a color-conversion light-emitting element 30, a second light-emitting element 40, and a first light-emitting element 20 stacked on a substrate 10 along a first direction M. The first direction M is perpendicular to the substrate 10. The color-conversion light-emitting element 30 is disposed on the substrate 10, the second light-emitting element 40 is disposed on the side of the color-conversion light-emitting element 30 away from the substrate 10, and the first light-emitting element 20 is disposed on the side of the second light-emitting element 40 away from the color-conversion light-emitting element 30.

[0038] Furthermore, the light-emitting structure may also include a bonding layer to bond the color-converting light-emitting element 30, the second light-emitting element 40, and the first light-emitting element 20 to the substrate 10 along a first direction M; the light-emitting structure includes a first bonding layer 51 disposed between the substrate 10 and the color-converting light-emitting element 30, a second bonding layer 52 disposed between the color-converting light-emitting element 30 and the second light-emitting element 40, and a third bonding layer 53 disposed between the second light-emitting element 40 and the first light-emitting element 20; wherein, the color-converting light-emitting element 30 is connected to the substrate 10 through the first bonding layer 51, the second light-emitting element 40 is connected to the side of the color-converting light-emitting element 30 away from the substrate 10 through the second bonding layer 52, and the first light-emitting element 20 is connected to the side of the second light-emitting element 40 away from the color-converting light-emitting element 30 through the third bonding layer 53.

[0039] In one embodiment, the first bonding layer 51 may include Au-Au bonding, Au-Sn bonding, Au-In bonding, Ti-Ti bonding, and Cu-Cu bonding. The thickness of the first bonding layer 51 may be greater than or equal to 0.1 micrometers and less than or equal to 3 micrometers. In addition to its bonding function, the first bonding layer 51 may also reflect light, so that the light irradiated in the light-emitting structure toward the substrate 10 can be reflected back to improve the light extraction efficiency.

[0040] The materials of the second bonding layer 52 and the third bonding layer 53 may include transparent resin materials or silicon oxide materials, and the thickness of the second bonding layer 52 and the thickness of the third bonding layer 53 may be greater than or equal to 0.1 micrometers and less than or equal to 5 micrometers, so that the second bonding layer 52 and the third bonding layer 53 can be transparent while playing a bonding role, so as to avoid affecting the light emission of the light-emitting structure.

[0041] In addition, the display panel also includes at least one first electrode 61 and a plurality of second electrodes 62 connected to the light-emitting structure, and the color-converting light-emitting element 30, the second light-emitting element 40 and the first light-emitting element 20 are all connected to the first electrode 61, and the color-converting light-emitting element 30, the second light-emitting element 40 and the first light-emitting element 20 are each independently connected to a second electrode 62; a circuit unit (not shown in the figure) is also provided in the substrate 10, and the first electrode 61 and the second electrode 62 are all connected to the circuit unit in the substrate 10 to realize signal transmission so that the color-converting light-emitting element 30, the second light-emitting element 40 and the first light-emitting element 20 can emit light.

[0042] It should be noted that the display panel also includes an insulating layer 70, which covers the locations where the first electrode 61 and the second electrode 62 are electrically connected to the light-emitting structure.

[0043] In this embodiment of the invention, the first light-emitting element 20 includes a first color light-emitting layer 21. The first color light-emitting layer 21 may include a light-emitting layer and an N-type doped layer and a P-type doped layer located on both sides of the light-emitting layer. One of the N-type doped layer and the P-type doped layer is connected to the first electrode 61, and the other is connected to the second electrode 62. For example, the first electrode 61 may be a P electrode and connected to the P-type doped layer, and the second electrode 62 may be an N electrode and connected to the N-type doped layer.

[0044] In one embodiment, the first color can be blue, and in the first color light-emitting layer 21, the n-type doped layer includes one or more of GaN, AlGaN, and AlInGaN, the material of the light-emitting layer includes InGaN / GaN quantum well material, and the p-type doped layer includes GaN material.

[0045] In one embodiment, in the first color emitting layer 21, a periodic stress adjustment layer and a current diffusion layer are further disposed between the N-type doped layer and the emitting layer, and a periodic stress adjustment layer and a current diffusion layer are further disposed between the P-type doped layer and the emitting layer, so as to enhance stress release and lateral current diffusion in the first color emitting layer 21 and improve the luminous efficiency of the first color emitting layer 21.

[0046] The second light-emitting element 40 includes a fourth color light-emitting layer 41, and the fourth color light-emitting layer 41 may include a light-emitting layer and an N-type doped layer and a P-type doped layer located on both sides of the light-emitting layer. One of the N-type doped layer and the P-type doped layer is connected to the first electrode 61, and the other is connected to the second electrode 62. For example, the first electrode 61 may be a P electrode and connected to the P-type doped layer, and the second electrode 62 may be an N electrode and connected to the N-type doped layer.

[0047] In one embodiment, the fourth color can be green, and in the fourth color light-emitting layer 41, the n-type doped layer includes one or more of GaN, AlGaN, and AlInGaN, the material of the light-emitting layer includes InGaN / GaN quantum well material, and the p-type doped layer includes GaN material.

[0048] In one embodiment, in the fourth color emitting layer 41, a periodic stress adjustment layer and a current diffusion layer are further disposed between the N-type doped layer and the emitting layer, and a periodic stress adjustment layer and a current diffusion layer are further disposed between the P-type doped layer and the emitting layer, so as to enhance stress release and lateral current diffusion in the fourth color emitting layer 41 and improve the luminous efficiency of the fourth color emitting layer 41.

[0049] The color conversion light-emitting element 30 includes a second color light-emitting layer 31 and a third color color conversion layer 32 stacked along the first direction M, and the third color color conversion layer 32 is disposed between the second color light-emitting layer 31 and the second light-emitting element 40. The luminous efficiency of the quantum well material of the third color is less than that of the second color light-emitting layer 31. That is, in this embodiment of the invention, the second color light-emitting layer 31 with higher luminous efficiency is used to emit light, so as to excite the third color color conversion layer 32 to emit light, thereby improving the luminous efficiency of the second color in the light-emitting structure, and thus improving the brightness and display effect of the display panel.

[0050] In one embodiment, the third color quantum well material includes at least one of InGaN, GaN, AlGaInP, and GaInP quantum well materials.

[0051] Furthermore, the luminous efficiency of the quantum well material of the third color can be lower than that of the first color luminous layer 21 and the fourth color luminous layer 41. That is, in this embodiment of the invention, by improving the light-emitting element with the lowest luminous efficiency in the light-emitting structure, a second color luminous layer 31 with higher luminous efficiency is used to emit light, thereby exciting the third color conversion layer 32 to emit light, thus improving the luminous efficiency of the third color in the light-emitting structure and improving the display effect of the display panel. In addition, the luminous efficiency of the first color luminous layer 21 is greater than that of the fourth color luminous layer 41, and the first color luminous layer 21 is located above the fourth color luminous layer 41, thereby avoiding the excitation effect of the first color light with higher energy on the fourth color luminous layer 41, so as to prevent the first color light from affecting the normal light emission of the fourth color luminous layer 41.

[0052] In one embodiment, the color-conversion light-emitting element 30 is used to emit red light, i.e., the third color is red. The quantum well material of the third color can be an AlGaInP / GaInP quantum well material. The third-color color-conversion layer 32 is used to excite red light. Since the luminous efficiency of the blue and green quantum well materials is greater than that of the red quantum well material, the second color can be blue or green to improve the luminous efficiency of red light in the light-emitting structure. Figure 1 As shown, this embodiment uses blue as an example for description.

[0053] In one embodiment, the second color emitting layer 31 may include an emitting layer and N-type doped layers and P-type doped layers located on both sides of the emitting layer. One of the N-type doped layer and the P-type doped layer is connected to the first electrode 61, and the other is connected to the second electrode 62. For example, the first electrode 61 may be a P-electrode connected to the P-type doped layer, and the second electrode 62 may be an N-electrode connected to the N-type doped layer. Furthermore, in the second color emitting layer 31, the N-type doped layer includes one or more of GaN, AlGaN, and AlInGaN, the material of the emitting layer includes InGaN / GaN quantum well material, and the P-type doped layer includes GaN material.

[0054] In one embodiment, the material of the third color conversion layer 32 may include phosphor material or quantum dot material, for example, red quantum dot material, and the red quantum dot material may be CdSe (cadmium selenide) or perovskite or InP (indium phosphide), and its full width at half maximum (FWHM) may be between 30 nm and 50 nm.

[0055] Furthermore, in this embodiment of the invention, the light-emitting structure further includes a first reflective layer 33 disposed between the color-conversion light-emitting element 30 and the substrate 10, and a second Bragg reflective layer 34 disposed between the color-conversion light-emitting element 30 and the second light-emitting element 40. The first reflective layer 33 can reflect light of the second color and light of the third color, while the second Bragg reflective layer 34 can reflect light of the second color. It is understood that the first reflective layer 33 can reflect light irradiated towards the substrate 10 back to continue participating in light conversion or emission, thereby improving light emission efficiency. The second Bragg reflective layer 34 can reflect high-energy second-color light, such as blue light, back to prevent high-energy second-color light from irradiating the second light-emitting element 40 and exciting the fourth-color light-emitting layer 41, thus preventing the second-color light from affecting the normal light emission of the fourth-color light-emitting layer 41.

[0056] In one embodiment, the first reflective layer 33 may include a first Bragg reflective layer, and the first Bragg reflective layer may include a first sub-section and a second sub-section stacked along a first direction M. The first sub-section may reflect light of a second color, while the second sub-section may reflect light of a third color. The vertical positions of the first and second sub-sections are not limited. The first sub-section includes multiple first sub-layers and multiple second sub-layers stacked and alternately arranged along the first direction M, i.e., a second sub-layer is spaced apart from adjacent first sub-layers by one second sub-layer, and a first sub-layer is spaced apart from adjacent second sub-layers by one first sub-layer. The second sub-section includes multiple third sub-layers and multiple fourth sub-layers stacked and alternately arranged along the first direction M, i.e., a fourth sub-layer is spaced apart from adjacent third sub-layers by one fourth sub-layer, and a third sub-layer is spaced apart from adjacent fourth sub-layers. The second Bragg reflective layer 34 includes multiple fifth sub-layers and multiple sixth sub-layers stacked and alternately arranged along the first direction M, i.e., a sixth sub-layer is spaced apart from adjacent fifth sub-layers, and a fifth sub-layer is spaced apart from adjacent sixth sub-layers by one fifth sub-layer.

[0057] The materials for the first, third, and fifth sublayers can all be silicon oxide, such as SiO2, while the materials for the second, fourth, and sixth sublayers can all be titanium oxide, such as Ti2O3.

[0058] In one embodiment, the number of the first sub-layer, the second sub-layer, the third sub-layer, the fourth sub-layer, the fifth sub-layer, and the sixth sub-layer can all be 15.

[0059] Furthermore, in this embodiment of the invention, the thicknesses of the first sub-layer, the second sub-layer, the third sub-layer, the fourth sub-layer, the fifth sub-layer, and the sixth sub-layer are designed so that the first Bragg reflector layer and the second Bragg reflector layer 34 can satisfy the above-mentioned purpose of reflecting light.

[0060] The first sub-layer can reflect light of the second color, the second sub-layer can reflect light of the third color, and the second Bragg reflector layer 34 can reflect light of the second color. The thickness of the first sub-layer and the thickness of the second sub-layer are both equal to one-quarter of the wavelength of the second color light. For example, if the second color is blue and the wavelength of the second color light is 455nm, then the thickness of the first sub-layer and the thickness of the second sub-layer are both equal to 113.7nm.

[0061] The thickness of the third sublayer and the thickness of the fourth sublayer are both equal to one-quarter of the wavelength of the third color light; for example, if the third color is red and the wavelength of the third color light is 630nm, then the thickness of the third sublayer and the thickness of the fourth sublayer are both equal to 157.5nm.

[0062] The thickness of the fifth sublayer and the thickness of the sixth sublayer are both equal to one-quarter of the wavelength of the second color light. For example, if the second color is blue and the wavelength of the second color light is 455nm, then the thickness of the fifth sublayer and the thickness of the sixth sublayer are both equal to 113.7nm.

[0063] It should be noted that, in this embodiment of the invention, by providing a first reflective layer 33 and a second Bragg reflective layer 34 on opposite sides of the color conversion light-emitting element 30, a microcavity is formed between the first reflective layer 33 and the second Bragg reflective layer 34, which can filter the second color light while further improving the light extraction efficiency of the third color light.

[0064] As mentioned above, in this embodiment of the invention, a second color light-emitting layer 31 and a third color color conversion layer 32 are stacked in the color conversion light-emitting element 30. The luminous efficiency of the quantum well material of the third color is relatively low and lower than that of the second color light-emitting layer 31. That is, the present invention uses the second color light-emitting layer 31 with higher luminous efficiency to emit light, so as to excite the third color conversion layer 32 to emit the third color light, thereby improving the luminous efficiency of the third color in the display panel and improving the brightness and display effect of the display panel.

[0065] In another embodiment of the present invention, please refer to Figure 2 This embodiment and Figure 1 The difference in the embodiment shown is that the first reflective layer 33 is reused as a bonding metal layer, so the material of the first reflective layer 33 can be a conductive and reflective metal material. The color conversion light-emitting element 30 is connected to the substrate 10 through the bonding metal layer, and can be connected to the circuit unit (not shown in the figure) in the substrate 10 through the bonding metal layer.

[0066] In this design, both the second light-emitting element 40 and the first light-emitting element 20 are connected to the first electrode 61, and each of the second light-emitting element 40 and the first light-emitting element 20 is independently connected to a second electrode 62. Both the first electrode 61 and the second electrode 62 are connected to a circuit unit in the substrate 10. The color-converting light-emitting element 30 is connected to the circuit unit in the substrate 10 via a bonding metal layer. Furthermore, the color-converting light-emitting element 30 is also connected to the first electrode 61 or to a second electrode 62. That is, the first reflective layer 33, while serving as a bonding metal layer, can also be reused as either the first electrode 61 or the second electrode 62. Figure 2 Taking the bonding metal layer reused as the first electrode 61 as an example.

[0067] Continuing from the above, this embodiment, while improving the luminous efficiency of the third color, reuses the first reflective layer 33 as a bonding metal layer and electrode, thereby reducing the number of first electrodes 61 or second electrodes 62 in the color conversion light-emitting element 30. Therefore, only a step needs to be reserved on one side of the color conversion light-emitting element 30 to connect the first electrode 61 or second electrode 62, while the other side does not need to be etched to form a step. This increases the luminous area of ​​the color conversion light-emitting element 30, further improving the luminous efficiency of the third color in the display panel. Correspondingly, since one side of the color conversion light-emitting element 30 does not need a step, the second light-emitting element 40 and the first light-emitting element 20 can also extend outwards on the side of the color conversion light-emitting element 30 that does not require a step. This also increases the luminous area of ​​the second light-emitting element 40 and the first light-emitting element 20, improving their luminous efficiency. Therefore, this embodiment, compared to... Figure 1 In the embodiment shown, the luminous efficiency of the first light-emitting element 20, the color-conversion light-emitting element 30, and the second light-emitting element 40 can be improved without increasing the area of ​​the light-emitting structure, thereby reducing the power consumption of the display panel.

[0068] In another embodiment of the present invention, please refer to Figure 3 This embodiment and Figure 1 The difference in the embodiment shown is that the light-emitting structure includes a color-conversion light-emitting element 30 disposed on the substrate 10 and a first light-emitting element 20 disposed on the side of the color-conversion light-emitting element 30 away from the substrate 10.

[0069] In this embodiment, the color conversion light-emitting element 30 includes a second color light-emitting layer 31 and a third color color conversion layer 32 stacked along the first direction M, and the luminous efficiency of the second color light-emitting layer 31 is greater than the luminous efficiency of the quantum well material of the third color.

[0070] In one embodiment, the first color can be blue or green, the second color can also be blue or green, and the third color can be red. Since the luminous efficiency of the quantum well material that emits red light is low, this embodiment uses a second color emitting layer 31 with higher luminous efficiency, such as blue or green, to emit light, thereby exciting the third color conversion layer 32 to emit red light, which improves the luminous efficiency of red light in the emitting structure and improves the brightness and display effect of the display panel.

[0071] Furthermore, the light-emitting structure in this embodiment also includes a first reflective layer 33 disposed between the color-conversion light-emitting element 30 and the substrate 10, and a second Bragg reflective layer 34 disposed between the color-conversion light-emitting element 30 and the first light-emitting element 20. In this embodiment, the structures of the first reflective layer 33 and the second Bragg reflective layer 34 can be the same as those of the first reflective layer 33 and the second Bragg reflective layer 34. Figure 1 The embodiments shown are the same and will not be described again here.

[0072] As mentioned above, in this embodiment of the invention, a second color light-emitting layer 31 and a third color color conversion layer 32 are stacked in the color conversion light-emitting element 30. The luminous efficiency of the quantum well material of the third color is relatively low and lower than that of the second color light-emitting layer 31. That is, the present invention uses the second color light-emitting layer 31 with higher luminous efficiency to emit light, so as to excite the third color conversion layer 32 to emit the third color light, thereby improving the luminous efficiency of the third color in the display panel and improving the brightness and display effect of the display panel.

[0073] In other embodiments of the present invention, the second color may also be ultraviolet light, and the second color emitting layer 31 may also emit ultraviolet light, that is, ultraviolet light is used to excite the third color conversion layer 32 to emit light of the third color, such as red light.

[0074] In addition, this embodiment of the invention also provides a method for manufacturing the display panel described in the above embodiments. Please refer to... Figure 1 , Figures 4 to 15 The manufacturing method of this display panel includes the following steps:

[0075] First, circuit units are formed on substrate 10, and the circuit units may include a pixel driver array.

[0076] Next, a second color light-emitting layer 31 is formed on the first sapphire substrate 81, wherein the second color can be blue, and the second color light-emitting layer 31 includes a light-emitting layer formed on the first sapphire substrate 81 and an N-type doped layer and a P-type doped layer located on opposite sides of the light-emitting layer; in one embodiment, the n-type doped layer includes one or more of GaN, AlGaN, and AlInGaN, the material of the light-emitting layer includes InGaN / GaN quantum well material, and the P-type doped layer includes GaN material.

[0077] Then, a first reflective layer 33 is formed on the side of the second color emitting layer 31 away from the first sapphire substrate 81. The first reflective layer 33 includes a first Bragg reflective layer, such as... Figure 4 As shown, the first Bragg reflector layer may include a first sub-section and a second sub-section stacked along the first direction M. The first sub-section can reflect light of a second color, while the second sub-section can reflect light of a third color. The vertical positions of the first and second sub-sections are not limited. The first sub-section includes multiple first sub-layers and multiple second sub-layers stacked and alternately arranged along the first direction M, i.e., a second sub-layer is spaced apart from two adjacent first sub-layers, and a first sub-layer is spaced apart from two adjacent second sub-layers. The second sub-section includes multiple third sub-layers and multiple fourth sub-layers stacked and alternately arranged along the first direction M, i.e., a fourth sub-layer is spaced apart from two adjacent third sub-layers, and a third sub-layer is spaced apart from two adjacent fourth sub-layers.

[0078] The first and third sublayers can be made of silicon oxide, such as SiO2, while the second and fourth sublayers can be made of titanium oxide, such as Ti2O3.

[0079] In one embodiment, the number of the first sub-layer, the number of the second sub-layer, the number of the third sub-layer, and the number of the fourth sub-layer can all be 15.

[0080] Furthermore, the first sub-layer can reflect light of the second color, and the second sub-layer can reflect light of the third color. The thickness of the first sub-layer and the thickness of the second sub-layer are both equal to one-quarter of the wavelength of the second color light. For example, if the second color is blue and the wavelength of the second color light is 455nm, then the thickness of the first sub-layer and the thickness of the second sub-layer are both equal to 113.7nm.

[0081] The thickness of the third sublayer and the thickness of the fourth sublayer are both equal to one-quarter of the wavelength of the third color light; for example, if the third color is red and the wavelength of the third color light is 630nm, then the thickness of the third sublayer and the thickness of the fourth sublayer are both equal to 157.5nm.

[0082] A first bonding layer 51 is used to connect the first reflective layer 33 and the substrate 10 together, and the second color emitting layer 31 is located on the side of the first reflective layer 33 away from the substrate 10, such as... Figure 5 and Figure 6 As shown.

[0083] In one embodiment, the first bonding layer 51 may include Au-Au bonding, Au-Sn bonding, Au-In bonding, Ti-Ti bonding, and Cu-Cu bonding. The thickness of the first bonding layer 51 may be greater than or equal to 0.1 micrometers and less than or equal to 3 micrometers. In addition to its bonding function, the first bonding layer 51 may also reflect light, so that light irradiated toward the substrate 10 can be reflected back to improve the light extraction efficiency.

[0084] Then, the first sapphire substrate 81 can be removed using laser lift-off or wet chemical etching, such as... Figure 7 and Figure 8 As shown.

[0085] Next, a third color conversion layer 32 and a second Bragg reflector layer 34 are sequentially formed on the side of the second color emitting layer 31 away from the substrate 10, as shown below. Figure 8 and Figure 9 As shown.

[0086] In one embodiment, the material of the third color conversion layer 32 may include phosphor material or quantum dot material, for example, red quantum dot material, and the red quantum dot material may be CdSe (cadmium selenide) or perovskite or InP (indium phosphide), and its full width at half maximum (FWHM) may be between 30 nm and 50 nm.

[0087] In one embodiment, the second Bragg reflector layer 34 includes a plurality of fifth sub-layers and a plurality of sixth sub-layers stacked and alternately arranged along the first direction M, wherein there is a sixth sub-layer between two adjacent fifth sub-layers and a fifth sub-layer between two adjacent sixth sub-layers.

[0088] The fifth sublayer can be made of silicon oxide, such as SiO2, and the sixth sublayer can be made of titanium oxide, such as Ti2O3. The number of both the fifth and sixth sublayers can be 15.

[0089] The second Bragg reflector layer 34 can reflect light of the second color. The thickness of the fifth sublayer and the thickness of the sixth sublayer are both equal to one-quarter of the wavelength of the second color light. For example, if the second color is blue and the wavelength of the second color light is 455nm, then the thickness of the fifth sublayer and the thickness of the sixth sublayer are both equal to 113.7nm.

[0090] Further, a second light-emitting element 40 is formed on the second sapphire substrate 82, and the second light-emitting element 40 includes a fourth color light-emitting layer 41 formed on the second sapphire substrate 82. In one embodiment, the fourth color can be green, and the fourth color light-emitting layer 41 can include a light-emitting layer and an N-type doped layer and a P-type doped layer located on opposite sides of the light-emitting layer. In the fourth color light-emitting layer 41, the n-type doped layer includes one or more of GaN, AlGaN, and AlInGaN, the material of the light-emitting layer includes InGaN / GaN quantum well material, and the P-type doped layer includes GaN material.

[0091] In one embodiment, in the fourth color emitting layer 41, a periodic stress adjustment layer and a current diffusion layer are further disposed between the N-type doped layer and the emitting layer, and a periodic stress adjustment layer and a current diffusion layer are further disposed between the P-type doped layer and the emitting layer, so as to enhance stress release and lateral current diffusion in the fourth color emitting layer 41 and improve the luminous efficiency of the fourth color emitting layer 41.

[0092] Next, the fourth color emitting layer 41 is connected to the side of the second Bragg reflective layer 34 away from the substrate 10 via the second bonding layer 52, as shown below. Figure 10 and Figure 11 As shown.

[0093] In one embodiment, the material of the second bonding layer 52 may include a transparent resin material or a silicon oxide material, and the thickness of the second bonding layer 52 may be greater than or equal to 0.1 micrometers and less than or equal to 5 micrometers, so that the second bonding layer 52 can be transparent while playing a bonding role, so as to avoid affecting the light emission of the light-emitting structure.

[0094] Then, the second sapphire substrate 82 can be removed using laser lift-off or wet chemical etching, such as... Figure 12 As shown.

[0095] Next, a first light-emitting element 20 is formed on the third sapphire substrate 83, and the first light-emitting element 20 includes a first color light-emitting layer 21 formed on the third sapphire substrate 83, such as... Figure 13 As shown.

[0096] In one embodiment, the first color may be blue, and the first color emitting layer 21 may include an emitting layer and an N-type doped layer and a P-type doped layer located on opposite sides of the emitting layer. In the first color emitting layer 21, the n-type doped layer includes one or more of GaN, AlGaN, and AlInGaN, the material of the emitting layer includes InGaN / GaN quantum well material, and the P-type doped layer includes GaN material.

[0097] In one embodiment, in the first color emitting layer 21, a periodic stress adjustment layer and a current diffusion layer are further disposed between the N-type doped layer and the emitting layer, and a periodic stress adjustment layer and a current diffusion layer are further disposed between the P-type doped layer and the emitting layer, so as to enhance stress release and lateral current diffusion in the first color emitting layer 21 and improve the luminous efficiency of the first color emitting layer 21.

[0098] Furthermore, the first color emitting layer 21 is connected to the side of the fourth color emitting layer 41 away from the substrate 10 via the third bonding layer 53, such as... Figure 14 As shown.

[0099] In one embodiment, the material of the third bonding layer 53 may include a transparent resin material or a silicon oxide material, and the thickness of the third bonding layer 53 may be greater than or equal to 0.1 micrometers and less than or equal to 5 micrometers, so that the third bonding layer 53 can be transparent while playing a bonding role, so as to avoid affecting the light emission of the light-emitting structure.

[0100] Furthermore, the third sapphire substrate 83 can be removed using laser lift-off or wet chemical etching, such as... Figure 15 As shown.

[0101] Finally, for Figure 14The stacked structure after removing the third sapphire substrate 83 is patterned, specifically the color-converting light-emitting element 30, the second light-emitting element 40, and the first light-emitting element 20 are patterned to form stepped sides to accommodate electrodes; then, at least one first electrode 61 and multiple second electrodes 62 are formed, such as... Figure 1 As shown.

[0102] In the first color emitting layer 21, one of the N-type doped layer and the P-type doped layer is connected to the first electrode 61, and the other is connected to the second electrode 62. For example, the first electrode 61 can be a P electrode and connected to the P-type doped layer, and the second electrode 62 can be an N electrode and connected to the N-type doped layer.

[0103] In the fourth color emitting layer 41, one of the N-type doped layer and the P-type doped layer is connected to the first electrode 61, and the other is connected to the second electrode 62. For example, the first electrode 61 can be a P electrode and connected to the P-type doped layer, and the second electrode 62 can be an N electrode and connected to the N-type doped layer.

[0104] In the second color emitting layer 31, one of the N-type doped layer and the P-type doped layer is connected to the first electrode 61, and the other is connected to the second electrode 62. For example, the first electrode 61 can be a P electrode and connected to the P-type doped layer, and the second electrode 62 can be an N electrode and connected to the N-type doped layer.

[0105] As mentioned above, in this embodiment of the invention, a second color light-emitting layer 31 and a third color color conversion layer 32 are stacked in the color conversion light-emitting element 30. The luminous efficiency of the quantum well material of the third color is relatively low and lower than that of the second color light-emitting layer 31. That is, the present invention uses the second color light-emitting layer 31 with higher luminous efficiency to emit light, so as to excite the third color conversion layer 32 to emit the third color light, thereby improving the luminous efficiency of the third color in the display panel and improving the brightness and display effect of the display panel.

[0106] In addition, embodiments of the present invention also provide a display device, which includes the display panel described in the above embodiments.

[0107] The display device may include televisions, computers, mobile phones, tablets, VR or AR display devices, etc.

[0108] The display device provided in this embodiment of the invention has the same beneficial effects as the display panel described above, since it is provided with the display panel described above.

[0109] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0110] The above provides a detailed description of a display panel and display device provided by the embodiments of the present invention. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only for the purpose of helping to understand the technical solutions and core ideas of the present invention. Those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A display panel, characterized in that, The display panel includes a substrate and at least one light-emitting structure disposed on the substrate, the light-emitting structure including: The first light-emitting element includes a first color light-emitting layer; A color-converting light-emitting element is stacked on the substrate along a first direction, which is perpendicular to the substrate. The first light-emitting element is disposed on the side of the color-converting light-emitting element away from the substrate. The color-converting light-emitting element includes a second color light-emitting layer and a third color color-converting layer stacked with the second color light-emitting layer along the first direction. The luminous efficiency of the quantum well material of the third color is lower than that of the first color light-emitting layer, and the luminous efficiency of the quantum well material of the third color is lower than that of the second color light-emitting layer, so as to excite the third color color-converting layer to emit light. The second light-emitting element is disposed between the first light-emitting element and the color-converting light-emitting element. The second light-emitting element includes a fourth color light-emitting layer. The luminous efficiency of the first color light-emitting layer is greater than that of the fourth color light-emitting layer, and the luminous efficiency of the third color quantum well material is less than that of the fourth color light-emitting layer. The light-emitting structure further includes a first reflective layer disposed between the color-converting light-emitting element and the substrate, and a second Bragg reflective layer disposed between the color-converting light-emitting element and the second light-emitting element; the first reflective layer reflects light of the second color and light of the third color, and the second Bragg reflective layer reflects light of the second color.

2. The display panel according to claim 1, characterized in that, The third color quantum well material includes at least one of InGaN, GaN, AlGaInP, and GaInP quantum well materials.

3. The display panel according to claim 1, characterized in that, The first reflective layer includes a first Bragg reflective layer, which includes a first sub-part and a second sub-part stacked along the first direction, wherein the first sub-part reflects light of the second color and the second sub-part reflects light of the third color. The first sub-part includes a plurality of first sub-layers and a plurality of second sub-layers stacked and alternately arranged; the second sub-part includes a plurality of third sub-layers and a plurality of fourth sub-layers stacked and alternately arranged; and the second Bragg reflector layer includes a plurality of fifth sub-layers and a plurality of sixth sub-layers stacked and alternately arranged. Wherein, the thickness of the first sub-layer and the thickness of the second sub-layer are both equal to one-quarter of the wavelength of the second color light, the thickness of the third sub-layer and the thickness of the fourth sub-layer are both equal to one-quarter of the wavelength of the third color light, and the thickness of the fifth sub-layer and the thickness of the sixth sub-layer are both equal to one-quarter of the wavelength of the second color light.

4. The display panel according to claim 3, characterized in that, The materials of the first sublayer, the third sublayer, and the fifth sublayer all include silicon oxide, while the materials of the second sublayer, the fourth sublayer, and the sixth sublayer all include titanium oxide.

5. The display panel according to claim 3, characterized in that, The display panel further includes at least one first electrode and a plurality of second electrodes connected to the light-emitting structure. At least the first color light-emitting layer and the fourth color light-emitting layer are both connected to the first electrode, and each of the first color light-emitting layer and the fourth color light-emitting layer is independently connected to one of the second electrodes.

6. The display panel according to claim 5, characterized in that, The first reflective layer is reused as a bonding metal layer, the color conversion light-emitting element is connected to the substrate through the bonding metal layer, and the second color light-emitting layer is connected to the first electrode or to a second electrode.

7. The display panel according to claim 1, characterized in that, The first color is blue or green, the second color is blue or green, and the third color is red.

8. The display panel according to claim 7, characterized in that, The fourth color may be the same as or different from the second color.

9. The display panel according to claim 1, characterized in that, The material of the third color conversion layer includes quantum dot materials or phosphor materials.

10. A display device, characterized in that, The display device includes a display panel as claimed in any one of claims 1 to 9.

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