Display panel and display device

Abstract

A display panel and a display device, relating to the technical field of display, and used for optimizing the light exit directivity of a device. The display panel comprises: a driving backplane (1); a light source (2), located on one side of the driving backplane (1) and used for emitting excitation light; a color conversion structure (3), located on the side of the light source (2) away from the driving backplane (1) and used for converting the excitation light into a target emitted light; a first reflective structure (4), located on the side of the color conversion structure (3) facing the driving backplane (1) and used for reflecting the target emitted light; and a second reflective structure (5), located on the side of the color conversion structure (3) away from the driving backplane (1), wherein the second reflective structure (5) is used for reflecting the excitation light and the target emitted light, and the reflectivity of the second reflective structure (5) to the target emitted light is less than the reflectivity of the first reflective structure (4) to the target emitted light.

Description

Display panel and display device

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on July 26, 2023, with application number 202310927884.4 and application name “Display Panel and Display Device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of display technology, and in particular to a display panel and a display device. Background Art

[0003] With the rapid development of display technology, near-eye display devices such as augmented reality (AR) and virtual reality (VR) have received widespread attention from researchers.

[0004] Currently, these near-eye display devices often use color conversion technology to address the issue of monolithic three-color integration. For example, by forming a color conversion structure on a blue micro LED to convert blue light into red or green light, a red microdisplay device or a green microdisplay device can be fabricated, thereby achieving the fabrication of a monolithic RGB (Red-Green-Blue) full-color microdisplay device. However, the light output shape of these microdisplay devices based on the color conversion structure is generally a Lambertian body with uniform spatial distribution, which makes it difficult to meet the light output collimation requirements of these near-eye display devices.

[0005] Summary of the Invention

[0006] In view of this, the present application provides a display panel and a display device for optimizing the light shape of the device.

[0007] An embodiment of the present application provides a display panel, comprising: a driving backplane; a light source, located on one side of the driving backplane, for emitting excitation light; a color conversion structure, located on the side of the light source facing away from the driving backplane, for converting the excitation light into target emission light; a first reflective structure, located on the side of the color conversion structure facing the driving backplane, for reflecting the target emission light; a second reflective structure, located on the side of the color conversion structure facing away from the driving backplane, the second reflective structure being used to reflect the excitation light and the target emission light; wherein the reflectivity of the second reflective structure to the target emission light is less than the reflectivity of the first reflective structure to the target emission light, so as to achieve a dominant light emission directionality on the front side of the device (the side facing away from the driving backplane).

[0008] In an embodiment of the present application, by arranging a first reflective structure and a second reflective structure on both sides of the color conversion structure, the first reflective structure and the second reflective structure can be used to form a resonant cavity that can act on the target emission light. The resonant cavity is a Fabry-Perot resonant cavity, that is, an FP resonant cavity. At this time, the cavity length of the resonant cavity can be set according to the emission peak position of the color conversion structure, that is, the distance between the first reflective structure and the second reflective structure is set, so that the target emission light in the resonant cavity has a narrower light output angle after coupling out, thereby optimizing its light output shape.

[0009] Existing micro-display devices can only achieve color conversion functions based on color conversion structures. If you want to achieve control of the device's light output direction, you can only do so in conjunction with the joint action of external micro-lenses. However, the micro-display device in the embodiment of the present application has its own resonant cavity structure that can control the light output direction of the target emitted light. The embodiment of the present application refers to this type of micro-display device as an RC-MD device. Based on the function of the resonant cavity, this type of RC-MD device directly has a narrow light output direction. It can meet the device light output collimation requirements of near-eye display devices such as AR and VR without matching external micro-lenses, thereby greatly reducing the process difficulty of the display panel.

[0010] In addition, in an embodiment of the present application, the second reflective structure on the side of the color conversion structure facing away from the driving backplane is also used to reflect the excitation light. A portion of the excitation light emitted by the light source may not be converted by the color conversion structure when it is transmitted toward the second reflective structure. However, based on the reflection effect of the second reflective structure on the excitation light, this portion of the excitation light will be reflected back by the second reflective structure and continue to be transmitted in the resonant cavity. In the process of continued transmission, the probability of it being converted by the color conversion structure can be increased, so that it can eventually be converted by the color conversion structure into the target emission light. Therefore, the embodiment of the present application can also increase the optical path of the excitation light, thereby effectively improving the light extraction efficiency and color conversion efficiency, preventing the excitation light from leaking and thereby reducing the color purity of the target emission light. In other words, under the condition of achieving the same color conversion efficiency, this structure can set the color conversion structure thinner to achieve the effect of saving costs and reducing the overall module thickness of the display panel.

[0011] In addition, the second reflective structure can also reflect ambient light to prevent ambient light from entering the resonant cavity and exciting the color conversion structure to emit light and generate stray light, thereby improving contrast and weakening artifacts.

[0012] In a feasible implementation, the first reflective structure is located between the light source and the color conversion structure.

[0013] In this structure, the resonant cavity formed by the first reflective structure and the second reflective structure is located on the side of the light source facing away from the driving backplane. The resonant cavity and the light source are independent of each other, and the membrane structure inside the resonant cavity is relatively simple, for example, it only includes a color conversion structure. At this time, the cavity length of the resonant cavity can be adjusted only by adjusting the thickness of the color conversion structure film, which makes the regulation of the cavity length of the resonant cavity simpler.

[0014] Furthermore, the first reflective structure is also used to transmit the excitation light.

[0015] Based on this structure, most of the excitation light emitted by the light source will be transmitted through the first reflective structure and enter the resonant cavity. For example, by designing a high-refractive / low-refractive distributed Bragg reflector structure, the transmittance of the excitation light is increased, thereby increasing the luminous flux of the excitation light transmitted in the resonant cavity, and then increasing the target emission light conversion amount, which helps to improve the light output brightness of the micro-display device. In addition, if a portion of the excitation light emitted by the light source is not converted by the color conversion structure when it is transmitted toward the color conversion structure, and is reflected back to the first reflective structure by the second reflective structure and is still not converted by the color conversion structure, then this portion of the excitation light can be transmitted toward the light source through the first reflective structure. Since electrodes are provided in the light source, this portion of blue light will be reflected back to the resonant cavity by the electrodes of the light source, such as the first electrode, and will eventually be converted into target emission light by the color conversion structure during the subsequent multiple round-trip transmissions.

[0016] Alternatively, the first reflective structure is also used to reflect excitation light; the light source includes an LED quantum well layer and a first electrode, the first electrode is located on the side of the LED quantum well layer close to the driving backplane, and the reflectivity of the first reflective structure to the excitation light is less than the reflectivity of the first electrode to the excitation light.

[0017] In this structure, a resonant cavity corresponding to the excitation light can also be formed between the first reflective structure and the first electrode. The excitation light resonant cavity and the target emission light resonant cavity formed between the first reflective structure and the second reflective structure are connected in series, and an RC-MD device having an excitation-emission series resonant cavity structure can be further formed. In this RC-MD device, by adjusting the cavity length of the resonant cavity formed by the first reflective structure and the first electrode, that is, adjusting the distance between the first reflective structure and the first electrode, the resonant cavity can be used to narrow the incident angle of the excitation light when entering the resonant cavity formed between the first reflective structure and the second reflective structure. Combined with the effect of the resonant cavity formed between the first reflective structure and the second reflective structure on the target emission light, this RC-MD device can have a narrower light output direction. This better light output directionality can enable better coupling between the device and the waveguide module, thereby having a better effect on improving the display effect, efficiency and power consumption of near-eye display systems such as AR and VR.

[0018] In a feasible embodiment, the light source includes an LED quantum well layer and a first electrode, wherein the first electrode is located on a side of the LED quantum well layer close to the driving backplane; the first reflective structure is multiplexed with the first electrode.

[0019] Electrodes in typical light sources are metal electrodes, which have a high reflectivity for both excitation light and target emission light. In this structure, the first reflective structure is directly reused with the first electrode, effectively utilizing the first electrode as the lower interface of the resonant cavity. This eliminates the need for a separate structure to serve as the first reflective structure, simplifying the process flow, reducing costs, and improving process integration.

[0020] Furthermore, the first electrode includes a sub-reflecting portion and a sub-connecting portion, the sub-reflecting portion is located between the sub-connecting portion and the LED quantum well layer, and the sub-connecting portion is bonded to the driving backplane; wherein the reflectivity of the sub-reflecting portion to the target emitted light is greater than the reflectivity of the sub-connecting portion to the target emitted light.

[0021] When the first reflective structure is reused with the first electrode, the first electrode needs to have both good conductivity and good reflective properties. By configuring the first electrode as two independent sub-reflective portions and a sub-connecting portion, the sub-reflective portion can be made more focused on having good reflective properties, while the sub-connecting portion can be made more focused on having good conductivity. This reduces the restrictions on the choice of materials for the first electrode. For example, materials with high conductivity but slightly low reflectivity, such as titanium or tungsten, can be selected to form the sub-connecting portion to ensure high connection reliability between the first electrode and the connecting metal of the driver backplane. A conductive distributed Bragg reflector can be selected as the sub-reflective portion to ensure high reflectivity of the sub-reflective portion to light.

[0022] In a feasible embodiment, the display panel includes a plurality of color conversion structures, one color conversion structure corresponds to one light source; the display panel also includes a pixel definition layer, at least part of the pixel definition layer is located between adjacent color conversion structures.

[0023] When multiple color conversion structures are spaced apart from each other, the pixel definition layer can be used to fill the gaps between adjacent color conversion structures, thereby improving the flatness of the second reflective structure disposed thereon, preventing the second reflective structure from being recessed in the gaps between the color conversion structures, and thereby preventing deviations in the cavity length of the resonant cavity.

[0024] In one feasible embodiment, a dielectric layer can be further disposed above the color conversion structure and pixel definition layer, covering the color conversion structure. The second reflective structure is located on the side of the dielectric layer facing away from the driver backplane. This dielectric layer can serve as a planarizing agent, further improving the flatness of the second reflective structure. This is particularly true when multiple color conversion structures convert the same target light, such as red, so that the resonant cavities corresponding to the different color conversion structures have the same cavity length. In this case, the pixel definition layer can be made of the same dielectric material as the dielectric layer.

[0025] In one feasible embodiment, a pixel definition layer is also located on the side of the color conversion structure facing away from the driver backplane, covering the color conversion structure. This allows the pixel definition layer to further flatten the structure, further improving the flatness of the second reflective structure. In particular, when the target light converted by multiple color conversion structures is the same color, such as red, the cavity lengths of the resonant cavities corresponding to the different color conversion structures are consistent, resulting in improved flatness of the second reflective structure. Greater consistency in the cavity lengths of the resonant cavities corresponding to the different color conversion structures improves the display quality of the micro-display panel. The dielectric layer also acts as an encapsulation layer, enhancing the water and oxygen stability of the quantum dot light-emitting pixels.

[0026] In a feasible embodiment, the light source includes an LED quantum well layer and a second electrode, and the second electrode is located on the side of the LED quantum well layer facing away from the driving backplane; the pixel definition layer and the first reflective structure and / or second reflective structure in contact therewith have conductive properties, and the pixel definition layer is also electrically connected to the second electrode.

[0027] When the pixel definition layer and the first reflective structure and / or second reflective structure in contact therewith both have conductive properties, typically, when the pixel definition layer is made of a high-conductivity metal film material, such as Al, Pt or Ag, the first electrode of the excitation light device can be electrically connected to the second electrode through the pixel definition layer, which can effectively improve the current diffusion uniformity of the second electrode and reduce the IR drop when the signal is transmitted on the second electrode.

[0028] In a feasible implementation, the color conversion structure covers the multiple light sources in a direction perpendicular to the plane where the display panel is located.

[0029] This setting method does not require pixelated design of the color conversion structure. Not only does it not need to set up the above-mentioned pixel definition layer, it also does not need to etch the color conversion structure, which simplifies the process flow. Moreover, the color conversion structure under this structure is flat across the entire surface, and the film layer of the second reflective structure above it will also have better flatness. At different positions, the distance difference between the first reflective structure and the second reflective structure is smaller.

[0030] After constructing the overall flattened resonant cavity color conversion layer, a color filter / black matrix is ​​constructed thereon to achieve pixelation, which can also realize the preparation of a pixelated micro display screen.

[0031] In a feasible embodiment, at least one of the first reflective structure and the second reflective structure includes a distributed Bragg reflector, and / or at least one of the first reflective structure and the second reflective structure includes a metal material, for example, a high-reflectivity metal material, so that the resonant cavity formed by the first reflective structure and the second reflective structure has a better regulating effect on the target emitted light, ensuring that the RC-MD device has a narrower light output angle.

[0032] In a feasible embodiment, the first reflective structure and the second reflective structure respectively include distributed Bragg reflectors, which include high refractive index layers and low refractive index layers that are periodically alternating. The logarithm of the period formed by the high refractive index layers and the low refractive index layers included in the second reflective structure is smaller than the logarithm of the period formed by the high refractive index layers and the low refractive index layers included in the first reflective structure. This ensures that the upper interface of the resonant cavity can emit light while forming a resonant cavity using the first reflective structure and the second reflective structure.

[0033] In a feasible embodiment, the reflectivity of the first reflective structure to the target emitted light is r1, 99%≤r1≤100%, and the reflectivity of the second reflective structure to the target emitted light is r2, 90%≤r2≤99%, so as to improve the effect of the resonant cavity on the target emitted light and ensure that the interface above the resonant cavity has the advantage of light output.

[0034] In a feasible embodiment, the target emission light converted by the color conversion structure is of the same color; wherein the distance between the first reflective structure and the second reflective structure is equal.

[0035] In this structure, since the color of the light converted by the color conversion structure is consistent, the emission peaks of the color conversion structure at different positions tend to be consistent. At this time, the cavity lengths of the resonant cavities at different positions can be set to be equal to control the light emission direction of the target emission light of the same color to the same extent.

[0036] In a feasible embodiment, the color conversion structure includes a first color conversion structure and a second color conversion structure, the target emission light converted by the first color conversion structure is a first color, and the target emission light converted by the second color conversion structure is a second color; wherein, at the position of the first color conversion structure, there is a first distance between the first reflective structure and the second reflective structure, and at the position of the second color conversion structure, there is a second distance between the first reflective structure and the second reflective structure, and the first distance and the second distance are different.

[0037] Since the colors of the first color conversion structure and the second color conversion structure are different, the emission peak position of the first color conversion structure and the emission peak position of the second color conversion structure are different. Therefore, the cavity lengths of the resonant cavities corresponding to the first color conversion structure and the second color conversion structure can be designed to be different, so that the cavity lengths of the resonant cavities corresponding to different color conversion structures are correlated with their emission peak positions, thereby effectively optimizing the light output shapes of different RC-MD devices.

[0038] Furthermore, if the first distance is greater than the second distance, the display panel further includes an adjustment layer, and the adjustment layer is located between the first color conversion structure and the second reflective structure.

[0039] When the cavity length of the resonant cavity corresponding to the first color conversion structure is greater than the cavity length of the resonant cavity corresponding to the second color conversion structure, the cavity length of the resonant cavity can be increased by adding an adjustment layer to the resonant cavity corresponding to the first color conversion structure. In this case, the film thickness of the first color conversion structure and the second color conversion structure can be kept consistent, thereby reducing the difference in color conversion efficiency between different color conversion structures.

[0040] Based on the same inventive concept, an embodiment of the present application further provides a display device, comprising the above-mentioned display panel.

[0041] Since the display device includes the above-mentioned display panel, the display device has a better device light output shape and can better meet the requirements of near-eye display devices such as AR and VR for device light output collimation. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without any creative work.

[0043] FIG1 is a schematic structural diagram of a display panel provided in an embodiment of the present application;

[0044] FIG2 is a schematic diagram of a quantum dot structure provided in an embodiment of the present application;

[0045] FIG3 is another schematic diagram of a quantum dot structure provided in an embodiment of the present application;

[0046] FIG4 is another schematic diagram of a quantum dot structure provided in an embodiment of the present application;

[0047] FIG5 is a schematic diagram of light transmission provided in an embodiment of the present application;

[0048] FIG6 is another schematic diagram of light transmission provided in an embodiment of the present application;

[0049] FIG7 is a schematic diagram of another structure of a display panel provided in an embodiment of the present application;

[0050] FIG8 is a schematic diagram of another light transmission method provided in an embodiment of the present application;

[0051] FIG9 is a schematic diagram of another structure of a display panel provided in an embodiment of the present application;

[0052] FIG10 is another schematic diagram of light transmission provided in an embodiment of the present application;

[0053] FIG11 is a schematic diagram of another structure of a display panel provided in an embodiment of the present application;

[0054] FIG12 is a schematic diagram of another structure of a display panel provided in an embodiment of the present application;

[0055] FIG13 is a schematic diagram of another structure of a display panel provided in an embodiment of the present application;

[0056] FIG14 is a schematic diagram of another structure of a display panel provided in an embodiment of the present application;

[0057] FIG15 is a schematic diagram of another structure of a display panel provided in an embodiment of the present application;

[0058] FIG16 is a process flow chart of a display panel provided in an embodiment of the present application;

[0059] FIG17 is another process flow chart of a display panel provided in an embodiment of the present application;

[0060] FIG18 is a schematic diagram of another structure of a display panel provided in an embodiment of the present application;

[0061] FIG19 is a flowchart of another process for producing a display panel according to an embodiment of the present application;

[0062] FIG20 is another process flow chart of a display panel provided in an embodiment of the present application;

[0063] FIG21 is a schematic diagram of another structure of a display panel provided in an embodiment of the present application;

[0064] FIG22 is another process flow chart of a display panel provided in an embodiment of the present application;

[0065] FIG23 is another process flow chart of a display panel provided in an embodiment of the present application;

[0066] FIG24 is another structural diagram of a display panel provided in an embodiment of the present application.

[0067] FIG25 is another process flow chart of a display panel provided in an embodiment of the present application;

[0068] FIG26 is another process flow chart of a display panel provided in an embodiment of the present application;

[0069] FIG27 is a schematic diagram of another structure of a display panel provided in an embodiment of the present application;

[0070] FIG28 is a schematic diagram of another structure of a display panel provided in an embodiment of the present application;

[0071] FIG29 is a schematic structural diagram of a display device provided in an embodiment of the present application;

[0072] FIG30 is a schematic diagram of an application scenario of the display device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0073] To make the objectives, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of this application, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without making any creative efforts shall fall within the scope of protection of this application.

[0074] The terms used in the embodiments of the present application are for the purpose of describing specific embodiments only and are not intended to limit the present application. The singular forms "a", "an", "the" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise.

[0075] As described in the background technology, the light shape of the micro-display device formed based on the color conversion material is difficult to meet the requirements of AR, VR and other near-eye display devices for the collimation of the device light. For this reason, the prior art generally integrates a micro-lens above the color conversion structure, and uses the micro-lens to further regulate the light output of the micro-display device. However, the selectivity of the micro-lens for the light output direction of the device is low, and the light collection effect is limited. Moreover, this method requires extremely high alignment accuracy between the light source, the color conversion structure and the micro-lens. If any two of them are not accurately aligned, it will seriously affect the final effect of the device's light output direction, resulting in a higher process difficulty.

[0076] In this regard, an embodiment of the present application provides a display panel, as shown in Figure 1, which is a structural schematic diagram of the display panel provided by an embodiment of the present application. The display panel includes a driving backplane 1, a light source 2, a color conversion structure 3, a first reflective structure 4 and a second reflective structure 5.

[0077] The light source 2 is located on one side of the driving backplane 1 and is used to emit excitation light. In the embodiment of the present application, the light source 2 is not limited to blue micro LEDs, but can also include ultraviolet light-emitting diodes, quantum dot light-emitting diodes, and organic light-emitting diodes.

[0078] The color conversion structure 3 is located on the side of the light source 2 facing away from the driving backplane 1 and is used to convert excitation light into target emission light. For example, it can convert the blue light emitted by the light source 2 into red or green light. In the embodiment of the present application, the material of the color conversion structure 3 may include quantum dot materials, phosphor materials, organic light-emitting materials, or doped phosphor materials. When the material of the color conversion structure 3 includes quantum dot materials, the quantum dot materials may include a core-shell structure composed of at least one of CdSe (cadmium selenide), CdS (cadmium sulfide), ZnSe (zinc selenide), ZnS (zinc sulfide), InP (indium phosphide), CdTe (cadmium telluride), ZnTe (zinc telluride), AgInGaS (silver indium gallium sulfide), GaP (gallium phosphide), ZnCdSe (zinc cadmium selenide), and / or an alloy structure composed of at least one of the above. Exemplarily, the quantum dot material includes at least one core-shell quantum dot material of CdSe / CdS, CdSe / ZnSe, CdS / ZnS, InP / ZnSe, InP / ZnSe / ZnS, ZnSe / ZnS, CdSe / ZnSe / ZnS, CdSe / CdS / ZnS, and InP / GaP; or, the quantum dot material includes at least one alloy quantum dot material of ZnCdSe / ZnSe, CdSeS, ZnCdS, ZnCdSe / ZnS, and AgInGaS / ZnS. In addition, when the material of the color conversion structure 3 includes quantum dot material, as shown in Figures 2 to 4, Figure 2 is a schematic diagram of the quantum dot structure provided in an embodiment of the present application, Figure 3 is another schematic diagram of the quantum dot structure provided in an embodiment of the present application, and Figure 4 is yet another schematic diagram of the quantum dot structure provided in an embodiment of the present application. The quantum dot structure in the quantum dot material may include a three-dimensional quantum dot 6 shown in Figure 2, a two-dimensional quantum sheet 7 shown in Figure 3, and a one-dimensional quantum rod 8 shown in Figure 4.

[0079] The first reflective structure 4 is located on a side of the color conversion structure 3 facing the driving backplane 1 and is used to reflect target emitted light.

[0080] The second reflective structure 5 is located on the side of the color conversion structure 3 facing away from the driving backplane 1. In the direction perpendicular to the plane of the driving backplane 1, the second reflective structure 5 overlaps with the first reflective structure 4. The second reflective structure 5 is used to reflect the excitation light and the target emission light, and the reflectivity of the second reflective structure 5 to the target emission light is less than the reflectivity of the first reflective structure 4 to the target emission light.

[0081] Exemplarily, the light source 2 is a blue micro LED, and the color conversion structure 3 is used to convert blue light into red light. The first reflective structure 4 is used to reflect red light, and the second reflective structure 5 is used to reflect blue light and red light.

[0082] In an embodiment of the present application, by arranging a first reflective structure 4 and a second reflective structure 5 on both sides of the color conversion structure 3, the first reflective structure 4 and the second reflective structure 5 can be used to form a resonant cavity that can act on the target emission light. In the drawings of the embodiment of the present application, the resonant cavity formed by the first reflective structure 4 and the second reflective structure 5 is represented by the figure mark RC1. The resonant cavity RC1 is a Fabry-Perot resonant cavity, that is, an FP resonant cavity. At this time, the cavity length of the resonant cavity RC1 can be set according to the emission peak position of the color conversion structure 3, that is, the distance between the first reflective structure 4 and the second reflective structure 5 can be set, so that the target emission light in the resonant cavity RC1 has a narrower light output angle after coupling out, thereby optimizing its light output shape.

[0083] For example, when the color conversion structure 3 includes quantum dot material, the cavity length d of the resonant cavity RC1 can be set to Where q is the number of resonant modes, which can be integers such as 1, 2, 3, etc., and λ QD is the quantum dot emission peak position, and n is the equivalent refractive index of the film layer between the first reflective structure 4 and the second reflective structure 5.

[0084] Combined with the above description of existing micro-display devices, it can be seen that existing micro-display devices can only realize the color conversion function based on the color conversion structure 3. If you want to achieve the regulation of the light output direction of the device, you can only do it in combination with the joint action of external micro-lenses. The micro-display device in the embodiment of the present application itself has a resonant cavity that can regulate the light output direction of the target emitted light. The embodiment of the present application refers to this type of micro-display device as an RC-MD (Resonant Cavity-Micro Display) device. Based on the effect of the resonant cavity, this type of RC-MD device directly has a narrower light output direction. It can meet the requirements of AR, VR and other near-eye display devices for device light output collimation without matching external micro-lenses, which can greatly reduce the process difficulty of the display panel.

[0085] It can be understood that since the reflectivity of the second reflective structure 5 to the target emitted light is lower than the reflectivity of the first reflective structure 4 to the target emitted light, when the target emitted light is transmitted back and forth in the resonant cavity RC1, each time the target emitted light is transmitted to the upper interface of the resonant cavity RC1 (the second reflective structure 5), a portion of the target emitted light can be interference-coupled out through the upper interface of the resonant cavity RC1. In the process of multiple back and forth transmissions of the target emitted light, a sufficient amount of front light output can be guaranteed.

[0086] Furthermore, in this embodiment of the present application, the second reflective structure 5 on the side of the color conversion structure 3 facing away from the driver backplate 1 is also used to reflect excitation light. As shown in FIG5 , which is a schematic diagram of light transmission provided by this embodiment of the present application, the dashed arrows in FIG5 represent excitation light (e.g., blue light), and the solid arrows represent target emission light (e.g., red light). A portion of the blue light emitted by the light source 2 may not be converted by the color conversion structure 3 when it is transmitted toward the second reflective structure 5. However, due to the reflection of the blue light by the second reflective structure 5, this portion of the blue light will be reflected back by the second reflective structure 5 and continue to propagate within the resonant cavity RC1. During this continued transmission, the probability of the blue light being converted by the color conversion structure 3 is increased, allowing it to ultimately be converted to red light by the color conversion structure 3. Therefore, this embodiment of the present application can also increase the optical path of the excitation light, thereby effectively improving light extraction efficiency and color conversion efficiency, preventing leakage of the excitation light and thereby reducing the color purity of the target emission light. In other words, while achieving the same color conversion efficiency, this structure can make the color conversion structure 3 thinner, thereby saving costs and reducing the overall module thickness of the display panel.

[0087] In addition, the second reflective structure 5 can also reflect ambient light to prevent the ambient light from entering the resonant cavity and stimulating the color conversion structure to emit light and generate stray light, thereby improving contrast and reducing artifacts.

[0088] It should be noted that, in the embodiments of the present application, the first reflective structure 4 being used to reflect the target light means that the first reflective structure 4 primarily reflects the target light, i.e., the first reflective structure 4 reflects the target light much more than it transmits it. Similarly, the second reflective structure 5 being used to reflect the excitation light and the target light means that the second reflective structure 5 primarily reflects the excitation light and the target light, i.e., the second reflective structure 5 reflects the excitation light and the target light much more than it transmits it.

[0089] In a feasible embodiment, referring again to FIG. 1 , the first reflective structure 4 is located between the light source 2 and the color conversion structure 3 .

[0090] In this structure, the resonant cavity RC1 formed by the first reflective structure 4 and the second reflective structure 5 is located on the side of the light source 2 facing away from the driving backplate 1. The resonant cavity RC1 and the light source 2 are independent of each other. The internal membrane structure of the resonant cavity RC1 is relatively simple, for example, it only includes the color conversion structure 3. At this time, the cavity length of the resonant cavity can be adjusted only by adjusting the film thickness of the color conversion structure 3, which makes the regulation of the cavity length of the resonant cavity simpler.

[0091] Furthermore, the first reflective structure 4 is also used to transmit the excitation light. For example, the light source 2 is a blue micro LED, the color conversion structure 3 is used to convert the blue light into red light, the first reflective structure 4 is used to transmit the blue light and reflect the red light, and the second reflective structure 5 is used to reflect the blue and red light.

[0092] Based on this structure, the excitation light emitted by light source 2 is mostly transmitted through first reflective structure 4 and enters resonant cavity RC1, increasing the luminous flux of the excitation light transmitted in resonant cavity RC1, thereby increasing the conversion amount of target emission light, which helps to improve the light output brightness of the microdisplay device. Moreover, as shown in Figure 6, Figure 6 is another light transmission schematic provided by an embodiment of the present application. The dotted arrows in Figure 6 represent excitation light (e.g., blue light), and the solid arrows represent target emission light (e.g., red light). A portion of the blue light emitted by light source 2 is not converted by the color conversion structure 3 when it is transmitted toward the color conversion structure 3. If it is still not converted by the color conversion structure 3 when it is reflected back to the first reflective structure 4 by the second reflective structure 5, then this portion of blue light can be transmitted toward light source 2 through the first reflective structure 4. Since light source 2 is provided with electrodes, this portion of blue light will be reflected back to resonant cavity RC1 by the electrodes of light source 2, such as first electrode 10, and thus ultimately converted to red light by the color conversion structure 3 during multiple subsequent round-trip transmissions.

[0093] In the above structure, the first reflective structure 4 may be designed as a distributed Bragg reflector (DBR) that transmits blue light and reflects red light.

[0094] It should be noted that the first reflective structure 4 transmitting the excitation light in the embodiments of the present application means that the first reflective structure 4 primarily transmits the excitation light. That is, the first reflective structure 4 transmits the excitation light much more than it reflects the excitation light. In the embodiments of the present application, the transmittance of the first reflective structure 4 to the excitation light can be between 90% and 100%.

[0095] Alternatively, as shown in Figures 7 and 8, Figure 7 is another structural schematic diagram of the display panel provided in an embodiment of the present application, and Figure 8 is another light transmission schematic diagram provided in an embodiment of the present application, in which the first reflective structure 4 is also used to reflect the excitation light. The light source 2 includes an LED quantum well layer 9 and a first electrode 10. The first electrode 10 is located on the side of the LED quantum well layer 9 close to the driving backplane 1. The reflectivity of the first reflective structure 4 to the excitation light is less than the reflectivity of the first electrode 10 to the excitation light. Exemplarily, the light source 2 is a blue light micro LED, the color conversion structure 3 is used to convert blue light into red light, and the first reflective structure 4 and the second reflective structure 5 are both used to reflect blue light and red light.

[0096] In this structure, a resonant cavity can also be formed between the first reflective structure 4 and the first electrode 10. In Figures 7 and 8, the resonant cavity formed between the first reflective structure 4 and the first electrode 10 is represented by the reference numeral RC2. The resonant cavity RC2 and the resonant cavity RC1 are connected in series to further form an RC-MD device having a series resonant cavity structure. In this RC-MD device, by adjusting the cavity length of the resonant cavity RC2, that is, adjusting the distance between the first reflective structure 4 and the first electrode 10, the resonant cavity RC2 can be used to narrow the incident angle of the excitation light when entering the resonant cavity RC1. Combined with the effect of the resonant cavity RC1 on the target emitted light, this RC-MD device can have a narrower light output direction. This better light output directionality can enable better coupling between the device and the waveguide module, thereby having a better effect on improving the display effect, efficiency, and power consumption of near-eye display systems such as AR and VR. Furthermore, this RC-MD device can also be combined with various light-collecting structures such as sidewall barriers and microlenses 15 to further control the light to achieve an extremely narrow device light output.

[0097] It can be understood that since the reflectivity of the first reflective structure 4 to the excitation light is lower than the reflectivity of the first electrode 10 to the excitation light, when the excitation light is transmitted back and forth in the resonant cavity RC2, each time the excitation light is transmitted to the upper interface of the resonant cavity RC2 (the first reflective structure 4), a portion of the target emission light can be coupled out through the upper interface of the resonant cavity RC2. In the process of multiple back and forth transmissions of the excitation light, it is possible to ensure that sufficient light is emitted into the resonant cavity RC1.

[0098] In the above structure, the first reflective structure 4 may be designed as a distributed Bragg reflector that reflects blue light and red light.

[0099] In a feasible embodiment, as shown in Figures 9 and 10, Figure 9 is another structural schematic diagram of the display panel provided in an embodiment of the present application, and Figure 10 is another transmission schematic diagram of light provided in an embodiment of the present application, the light source 2 includes an LED quantum well layer 9 and a first electrode 10, and the first electrode 10 is located on the side of the LED quantum well layer 9 close to the driving backplane 1. The first reflective structure 4 is multiplexed with the first electrode 10.

[0100] The electrodes in light source 2 are typically metal electrodes, which have a high reflectivity for both the excitation light and the target emission light. In this structure, the first reflective structure 4 is directly reused with the first electrode 10, that is, the first electrode 10 is used as the lower interface of the resonant cavity RC1. In this case, there is no need to separately configure another structure as the first reflective structure 4, which simplifies the process flow, reduces process costs, and improves process integration.

[0101] Furthermore, as shown in FIG11 , which is another structural schematic diagram of a display panel provided in an embodiment of the present application, the first electrode 10 includes a sub-reflecting portion 11 and a sub-connecting portion 12. The sub-reflecting portion 11 is located between the sub-connecting portion 12 and the LED quantum well layer 9, and the sub-connecting portion 12 is bonded to the driving backplane 1. The reflectivity of the sub-reflecting portion 11 to the target emitted light is greater than the reflectivity of the sub-connecting portion 12 to the target emitted light.

[0102] When the first reflective structure 4 is reused with the first electrode 10, the first electrode 10 needs to have both good electrical conductivity and good reflective performance. By configuring the first electrode 10 as two independent sub-reflective portions 11 and sub-connecting portions 12, the sub-reflective portion 11 can be made more focused on having good reflective performance, while the sub-connecting portion 12 can be made more focused on having good electrical conductivity. This reduces restrictions on the selection of materials for the first electrode 10. For example, materials with high electrical conductivity but slightly low reflectivity, such as titanium or tungsten, can be selected to form the sub-connecting portion 12, so as to ensure high connection reliability between the first electrode 10 and the connecting metal 22 of the driving backplane 1, while a conductive distributed Bragg reflector can be selected as the sub-reflective portion 11, so that the sub-reflective portion 11 has high reflectivity to light.

[0103] 1 , the display panel includes a plurality of color conversion structures 3 , one color conversion structure 3 corresponding to one light source 2 , and a pixel definition layer 13 , at least part of which is located between adjacent color conversion structures 3 .

[0104] When the display panel includes multiple color conversion structures 3, and each color conversion structure 3 corresponds to one light source 2, the display panel may include only a single-color RC-MD device, or may include multiple RC-MD devices, such as red, green, and blue. For example, multiple color conversion structures 3 are used only to convert excitation light into red light, in which case the display panel includes only red RC-MD devices. Alternatively, multiple color conversion structures 3 are used only to convert excitation light into green light, in which case the display panel includes only green RC-MD devices. Alternatively, some color conversion structures 3 are used to convert excitation light into red light, some are used to convert excitation light into green light, and some are used to convert excitation light into blue light, in which case the display panel includes red RC-MD devices, green RC-MD devices, and blue RC-MD devices.

[0105] When multiple color conversion structures 3 are spaced apart from each other, the pixel definition layer 13 can be used to fill the gaps between adjacent color conversion structures 3, thereby serving as a support layer to improve the flatness of the second reflective structure 5 disposed thereon, thereby preventing the second reflective structure 5 from being recessed in the gaps between the color conversion structures 3 and thereby preventing the cavity length of the resonant cavity RC1 from deviating.

[0106] Furthermore, a dielectric layer can be further disposed above the color conversion structure 3 and the pixel definition layer 13. This dielectric layer covers the color conversion structure 3, and the second reflective structure 5 is located on the side of the dielectric layer facing away from the driver backplane 1. This dielectric layer can provide a planarizing effect, further improving the flatness of the second reflective structure 5. This is particularly true when the target light converted by multiple color conversion structures 3 is the same color, such as red, so that the resonant cavities corresponding to the different color conversion structures 3 have the same cavity length. In this case, the pixel definition layer can be made of the same dielectric material as the dielectric layer.

[0107] Furthermore, as shown in Figure 12, Figure 12 is another structural schematic diagram of the display panel provided in an embodiment of the present application. The pixel definition layer 13 is also located on the side of the color conversion structure 3 facing away from the driving backplane 1. The pixel definition layer 13 covers the color conversion structure 3, and the second reflective structure 5 is located on the side of the pixel definition layer 13 facing away from the driving backplane 1.

[0108] At this point, the pixel definition layer 13 not only fills the gaps between the color conversion structures 3 but also covers them. This pixel definition layer 13 acts as a flattening layer, further improving the film flatness of the second reflective structure 5. In particular, when the light converted by multiple color conversion structures 3 is the same color, such as red, the cavity lengths of the resonant cavities RC1 corresponding to the different color conversion structures 3 are consistent, resulting in improved film flatness of the second reflective structure 5. The better the control of the cavity length consistency of the resonant cavities RC1 corresponding to the different color conversion structures 3, the better the display quality of the micro-display panel. The dielectric layer also acts as an encapsulation layer, improving the water and oxygen stability of the quantum dot light-emitting pixels. Considering the device's light output, the pixel definition layer corresponding to Figure 12 should be a transparent material, typically a dielectric thin film such as SiO2 or SiNx. In this case, the pixel definition layer 13 also serves as a pixel encapsulation layer, improving the stability of the color conversion layer material.

[0109] In one possible embodiment, referring again to FIG9 , the light source 2 includes an LED quantum well layer 9 and a second electrode 14 , wherein the second electrode 14 is located on a side of the LED quantum well layer 9 facing away from the driving backplane 1 . The pixel definition layer 13 and the first reflective structure 4 and / or the second reflective structure 5 in contact therewith are both conductive, and the pixel definition layer 13 is also electrically connected to the second electrode 14 .

[0110] In the above structure, the first electrode 10 and second electrode 14 of the light source 2 are located on opposite sides of the LED quantum well layer 9, respectively. The first electrode 10 can be the positive electrode and the second electrode 14 can be the negative electrode. In this case, the light source 2 can be a vertical micro LED. When the pixel definition layer 13 has conductive properties, the first reflective structure 4 and / or the second reflective structure 5 can be electrically connected to the second electrode 14 through the pixel definition layer 13, which can effectively improve the current diffusion uniformity of the second electrode 14 and reduce the voltage drop when the signal is transmitted on the second electrode 14. For example, referring to Figure 9, the first reflective structure 4 is reused with the first electrode 10, and the pixel definition layer 13 is electrically connected to the second electrode 14. Typical conductive pixel definition layer materials can be high-reflectivity metal materials such as Ag, Pt, and Al. In this case, the pixel definition layer 13 can also serve as a metal mesh current diffusion layer, improving the charge transfer performance of the second electrode 14, thereby improving voltage uniformity at different locations of the device and alleviating current crowding and IR drop.

[0111] In a feasible embodiment, as shown in Figure 13, Figure 13 is another structural schematic diagram of the display panel provided in an embodiment of the present application. In the direction perpendicular to the plane where the display panel is located, the color conversion structure 3 covers multiple light sources 2. At this time, the color conversion structure 3 is an entire film layer covering multiple light sources 2. At this time, the display panel can only include a monochrome RC-MD device.

[0112] This arrangement does not require pixelation of the color conversion structure 3. Not only does it not require the aforementioned pixel definition layer 13, but it also does not require etching of the color conversion structure 3, simplifying the process flow. Furthermore, the entire surface of the color conversion structure 3 under this structure is flat, and the film flatness of the second reflective structure 5 above it is also better. At different positions, the distance difference between the first reflective structure 4 and the second reflective structure 5 is smaller.

[0113] After constructing the overall flattened resonant cavity color conversion layer, a color filter / black matrix is ​​constructed thereon to achieve pixelation, which can also realize the preparation of a pixelated micro display screen.

[0114] In addition, in an embodiment of the present application, as shown in Figure 14, Figure 14 is another structural schematic diagram of the display panel provided in an embodiment of the present application. The display panel may further include a microlens 15, and the microlens 15 is located on the side of the second reflective structure 5 facing away from the drive backplane 1, and one microlens 15 may correspond to one light source 2. By further integrating the microlens 15 above the RC-MD device, the direction of the light emitted by the RC-MD device can be further regulated by the microlens 15 to make the final light output angle narrower. Moreover, the display panel may further include an encapsulation layer (not shown in the figure) to play an encapsulation and protection role.

[0115] It should be noted that, since the RC-MD device in the embodiment of the present application can already achieve a relatively narrow light emission angle, even if a microlens 15 is provided in the display panel in the embodiment of the present application, the microlens 15 only plays a further auxiliary role, such as narrowing the light emission angle to a narrower level. The requirement for the alignment accuracy of the microlens 15 in the embodiment of the present application is lower than the requirement for the alignment accuracy of the microlens in the prior art.

[0116] In a feasible embodiment, at least one of the first reflective structure 4 and the second reflective structure 5 includes a distributed Bragg reflector, and / or at least one of the first reflective structure 4 and the second reflective structure 5 includes a metal material, for example, a high-reflectivity metal material.

[0117] The following four structures are used as examples for explanation.

[0118] The first structure:

[0119] As shown in Figure 15, Figure 15 is another structural schematic diagram of the display panel provided in an embodiment of the present application. The first reflective structure 4 is reused with the first electrode 10 of the light source 2. At this time, the first reflective structure 4 includes a metal material, and the first reflective structure 4 can reflect the excitation light and the target emission light. The second reflective structure 5 includes a first distributed Bragg reflector 16 that can reflect the excitation light and the target emission light.

[0120] Exemplarily, the light source 2 is a blue light micro LED, the color conversion structure 3 is used to convert blue light into red light, the first reflective structure 4 (first electrode 10) reflects blue light and red light, and the second reflective structure 5 (first distributed Bragg reflector 16) reflects blue light and red light.

[0121] As shown in FIG. 16 , FIG. 16 is a process flow chart of a display panel provided in an embodiment of the present application. The process of manufacturing a display panel with such a structure may include:

[0122] Step A1: forming an LED epitaxial back plate 17 , wherein the epitaxial back plate 17 includes an epitaxial substrate 18 , a second epitaxial layer 19 , an LED quantum well layer 9 , a first epitaxial layer 20 and a first electrode 10 , which are stacked.

[0123] Step A2: Bond the LED epitaxial backplane 17 and the CMOS driver backplane 1. For example, the two can be bonded by wafer bonding, wherein the driver backplane 1 includes a driver substrate 21 and a connecting metal 22. The driver substrate 21 includes a driver circuit. The driver circuit may include transistor devices and wiring, etc. After bonding the epitaxial backplane 17 and the driver backplane 1, the first electrode 10 is electrically connected to the connecting metal 22, and then connected to the driver circuit in the driver substrate 21. Then, the epitaxial substrate 18 is removed.

[0124] Step A3: Etch the second epitaxial layer 19, the LED quantum well layer 9, the first epitaxial layer 20, the first electrode 10 and the connecting metal 22 to form an insulating layer 23 between adjacent light-emitting parts, and form a second electrode 14 covering the entire surface, thereby forming a plurality of independent light sources 2 including the second epitaxial layer 19, the LED quantum well layer 9, the first epitaxial layer 20, the first electrode 10 and the second electrode 14.

[0125] Step A4: A pixel definition layer 13 having openings is formed above the second electrode 14, and then a color conversion material is filled in the meshes of the grid layer by spin coating, photolithography, inkjet printing, etc. to form a plurality of color conversion structures 3 corresponding to the plurality of light sources 2.

[0126] Step A5: A high refractive index layer 26 and a low refractive index layer 27 are sequentially deposited on the color conversion structure 3 by a coating process such as physical vapor deposition (PVD) or atomic layer deposition (ALD). For example, a plurality of TiO 2 / A SiO2 layer or multiple SiO2 / HfO2 layers are formed to form a first distributed Bragg reflector 16 capable of reflecting both the excitation light and the target emission light. The distance between the first reflective structure 4 (first electrode 10) and the second reflective structure 5 (first distributed Bragg reflector 16) is correlated with the emission peak position of the color conversion structure 3.

[0127] Step A6: Dispose a plurality of micro lenses 15 above the first DBR 16 .

[0128] 15 and 16 are schematic diagrams based on an example in which the pixel definition layer 13 is located only between adjacent color conversion structures 3. When the pixel definition layer 13 also covers the color conversion structure 3, as shown in FIG17 , FIG17 is another process flow chart of the display panel provided in an embodiment of the present application, in which the above-mentioned step A4 can be replaced by step A4′.

[0129] Step A4′: A color conversion film 40 is formed on the second electrode 14 by spin coating or drop coating, and then a plurality of color conversion structures 3 corresponding to the plurality of light sources 2 are formed by photolithography or etching / lift-off. Then, a pixel definition layer 13 is formed so that a portion of the pixel definition layer 13 fills between adjacent color conversion structures 3 and a portion covers the color conversion structures 3.

[0130] It should be noted that, for the sake of simplicity, step A1, step A2 and step A6 are omitted in FIG17 . However, in its complete process flow, FIG17 should include step A1, step A2 and step A6 shown in FIG16 .

[0131] In this structure, the first reflective structure 4 reuses the first electrode 10 , and no additional structure is required to form the first reflective structure 4 , thereby simplifying the process flow.

[0132] The second structure:

[0133] As shown in Figure 18, Figure 18 is another structural schematic diagram of the display panel provided in an embodiment of the present application. The first reflective structure 4 is reused with the first electrode 10 of the light source 2, and the second reflective structure 5 includes a first metal film 24. At this time, the first reflective structure 4 and the second reflective structure 5 both include metal materials, and both can reflect the excitation light and the target emission light.

[0134] Exemplarily, the light source 2 is a blue light micro LED, the color conversion structure 3 is used to convert blue light into red light, the first reflective structure 4 (first electrode 10) reflects blue light and red light, and the second reflective structure 5 (first metal film 24) reflects blue light and red light.

[0135] As shown in FIG. 19 , FIG. 19 is a flowchart of another process for manufacturing a display panel according to an embodiment of the present application. The manufacturing process of a display panel with such a structure may include:

[0136] Step B1: forming an epitaxial back plate 17 , wherein the epitaxial back plate 17 includes an epitaxial substrate 18 , a second epitaxial layer 19 , an LED quantum well layer 9 , a first epitaxial layer 20 and a first electrode 10 that are stacked.

[0137] Step B2: Bond the epitaxial backplane 17 and the driving backplane 1. For example, the two can be bonded by wafer bonding, wherein the driving backplane 1 includes a driving substrate 21 and a connecting metal 22. The driving substrate 21 includes a driving circuit. The driving circuit may include transistor devices and wiring, etc. After bonding the epitaxial backplane 17 and the driving backplane 1, the first electrode 10 is electrically connected to the connecting metal 22, and then electrically connected to the driving in the driving substrate 21. Then, the epitaxial substrate 18 is removed.

[0138] Step B3: Etch the second epitaxial layer 19, the LED quantum well layer 9, the first epitaxial layer 20, the first electrode 10 and the connecting metal 22 to form an insulating layer 23 between adjacent light-emitting parts, and form a second electrode 14 covering the entire surface, thereby forming a plurality of independent light sources 2 including the second epitaxial layer 19, the LED quantum well layer 9, the first epitaxial layer 20, the first electrode 10 and the second electrode 14.

[0139] Step B4: A pixel definition layer 13 having openings is formed above the second electrode 14, and then a color conversion material is filled in the meshes of the grid layer by spin coating, photolithography, inkjet printing, etc. to form a plurality of color conversion structures 3 corresponding to the plurality of light sources 2.

[0140] Step B5: Depositing a metal material on the color conversion structure 3 by metal plating. The metal material includes, but is not limited to, Ag, Al, or a Mg:Ag alloy, to form a first metal film 24. The distance between the first reflective structure 4 (first electrode 10) and the second reflective structure 5 (first metal film 24) is correlated with the emission peak position of the color conversion structure 3.

[0141] Step B6: Disposing a plurality of micro lenses 15 above the first metal film 24 .

[0142] 18 and 19 are schematic diagrams based on an example in which the pixel definition layer 13 is located only between adjacent color conversion structures 3. When the pixel definition layer 13 also covers the color conversion structure 3, as shown in FIG20 , FIG20 is another process flow chart of the display panel provided in an embodiment of the present application, in which the above-mentioned step B4 can be replaced by step B4′.

[0143] Step B4': A color conversion film 40 is formed directly on the second electrode 14 by spin coating or drop coating, and then a plurality of color conversion structures 3 corresponding to the plurality of light sources 2 are formed by photolithography or etching / lift-off. Then, a pixel definition layer 13 is formed so that part of the pixel definition layer 13 fills between adjacent color conversion structures 3 and partly covers the color conversion structures 3. At this time, the pixel definition layer 13 can also serve as an encapsulation layer and a planarization layer.

[0144] It should be noted that, for the sake of simplicity, step B1, step B2 and step B6 are omitted in FIG20 , but in its complete process flow, FIG20 should include step B1, step B2 and step B6 shown in FIG19 .

[0145] Because precise control of the thickness of the distributed Bragg reflector (DBR) requires a more complex production process, in the second configuration, the second reflective structure 5 can be constructed as a metal film, eliminating the complex DBR fabrication process and reducing manufacturing complexity. Furthermore, metal films are typically fabricated using simple processes such as thermal evaporation / electron beam evaporation, which do not require a high-temperature process environment and minimize the loss of color conversion efficiency of the color conversion material. When quantum dot materials are used for the color conversion structure 3, the metal material exhibits good compatibility with the quantum dot material and does not compromise the fluorescence quantum yield (PL QY) of the quantum dot material itself.

[0146] Moreover, the inventors have discovered that in the embodiment of the present application, the thickness of the first metal film 24 can be set between 5 and 10 nm. At this time, the first metal film 24 can form a resonant cavity effect with the first electrode 10, which can greatly reduce the overall module thickness of the display panel compared to a distributed Bragg reflector with a thickness of 100 nm to 1 um.

[0147] The third structure:

[0148] As shown in Figure 21, Figure 21 is another structural schematic diagram of the display panel provided in an embodiment of the present application. The first reflective structure 4 includes a second distributed Bragg reflector 25 that can transmit excitation light and reflect target emission light, and the second reflective structure 5 includes a first distributed Bragg reflector 16 that can reflect excitation light and target emission light.

[0149] Exemplarily, the light source 2 is a blue light micro LED, the color conversion structure 3 is used to convert blue light into red light, the first reflective structure 4 (the second distributed Bragg reflector 25) transmits blue light and reflects red light, and the second reflective structure 5 (the first distributed Bragg reflector 16) reflects blue light and red light.

[0150] As shown in FIG. 22 , FIG. 22 is another process flow chart of a display panel provided in an embodiment of the present application. The process of manufacturing a display panel with this structure may include:

[0151] Step C1: forming an epitaxial back plate 17 , wherein the epitaxial back plate 17 includes an epitaxial substrate 18 , a second epitaxial layer 19 , an LED quantum well layer 9 , a first epitaxial layer 20 and a first electrode 10 that are stacked.

[0152] Step C2: Bond the epitaxial backplane 17 and the driving backplane 1. For example, the two can be bonded by wafer bonding, wherein the driving backplane 1 includes a driving substrate 21 and a connecting metal 22. The driving substrate 21 includes a driving circuit. The driving circuit may include transistor devices and wiring, etc. After bonding the epitaxial backplane 17 and the driving backplane 1, the first electrode 10 is electrically connected to the connecting metal 22, and then electrically connected to the driving in the driving substrate 21. Then, the epitaxial substrate 18 is removed.

[0153] Step C3: Etch the second epitaxial layer 19, the LED quantum well layer 9, the first epitaxial layer 20, the first electrode 10 and the connecting metal 22 to form an insulating layer 23 between adjacent light-emitting parts, and form a second electrode 14 covering the entire surface, thereby forming a plurality of independent light sources 2 including the second epitaxial layer 19, the LED quantum well layer 9, the first epitaxial layer 20, the first electrode 10 and the second electrode 14.

[0154] Step C4: A high refractive index layer 26 and a low refractive index layer 27 are sequentially deposited on the second electrode 14 by a coating process such as physical vapor deposition or atomic layer deposition, for example, to form multiple alternating TiO2 layers and SiO2 layers, or multiple alternating SiO2 layers and HfO2 layers, to form a first reflective structure 4 (second distributed Bragg reflector 25).

[0155] Step C5: A pixel definition layer 13 having openings is formed above the first reflective structure 4 (second distributed Bragg reflector 25). Then, a color conversion material is filled into the meshes of the mesh layer by spin coating, photolithography, inkjet printing, etc., to form a plurality of color conversion structures 3 corresponding one to one to the plurality of light sources 2.

[0156] Step C6: A high refractive index layer 26 and a low refractive index layer 27 are sequentially deposited on the color conversion structure 3 using a coating process such as physical vapor deposition or atomic layer deposition to form the second reflective structure 5 (first distributed Bragg reflector 16). The distance between the first reflective structure 4 (second distributed Bragg reflector 25) and the second reflective structure 5 (first distributed Bragg reflector 16) is correlated with the color conversion structure 3.

[0157] Step C7: Dispose a plurality of micro lenses 15 above the second reflective structure 5 (first DBR 16 ).

[0158] 21 and 22 are schematic diagrams based on an example in which the pixel definition layer 13 is located only between adjacent color conversion structures 3. When the pixel definition layer 13 also covers the color conversion structure 3, as shown in FIG23 , FIG23 is another process flow chart of the display panel provided in an embodiment of the present application, in which the above-mentioned step C5 can be replaced by step C5′.

[0159] Step C5': A color conversion film 40 is formed on the first reflective structure 4 (the second distributed Bragg reflector 25) by spin coating or drop coating, and then a plurality of color conversion structures 3 corresponding to the plurality of light sources 2 are formed by photolithography or etching / lift-off. Then, a pixel definition layer 13 is formed so that part of the pixel definition layer 13 fills between adjacent color conversion structures 3 and partly covers the color conversion structures 3. At this time, the pixel definition layer 13 can also serve as a planarization layer and an encapsulation layer.

[0160] It should be noted that, for the sake of simplicity, step C1, step C2, step C3 and step C7 are omitted in FIG23 , but in its complete process flow, FIG23 should include step C1, step C2, step C3 and step C7 shown in FIG22 .

[0161] In this structure, the first reflective structure 4 and the second reflective structure 5 both adopt a distributed Bragg reflector design. Generally speaking, compared with the metal layer, the distributed Bragg reflector has a higher reflectivity, so this design can achieve higher light extraction efficiency.

[0162] The fourth structure:

[0163] As shown in Figure 24, Figure 24 is another structural schematic diagram of the display panel provided in an embodiment of the present application. The first reflective structure 4 includes a second distributed Bragg reflector 25 that can transmit excitation light and reflect target emission light. The second reflective structure 5 includes a first metal film 24. At this time, the second reflective structure 5 includes a metal material, and the second reflective structure 5 can reflect excitation light and target emission light.

[0164] Exemplarily, the light source 2 is a blue light micro LED, the color conversion structure 3 is used to convert blue light into red light, the first reflective structure 4 (second distributed Bragg reflector 25) transmits blue light and reflects red light, and the second reflective structure 5 (first metal film 24) reflects blue light and red light.

[0165] As shown in FIG. 25 , FIG. 25 is another process flow chart of a display panel provided in an embodiment of the present application. The process of manufacturing a display panel with this structure may include:

[0166] Step D1: forming an LED epitaxial back plate 17 , wherein the LED epitaxial back plate 17 includes an epitaxial substrate 18 , a second epitaxial layer 19 , an LED quantum well layer 9 , a first epitaxial layer 20 and a first electrode 10 that are stacked.

[0167] Step D2: Bond the epitaxial backplane 17 and the driving backplane 1, such as a CMOS driving backplane. For example, the two can be bonded by wafer bonding, wherein the driving backplane 1 includes a driving substrate 21 and a connecting metal 22. The driving substrate 21 includes a driving circuit. The driving circuit may include transistor devices and wiring, etc. After bonding the epitaxial backplane 17 and the driving backplane 1, the first electrode 10 is electrically connected to the connecting metal 22, and then electrically connected to the driving in the driving substrate 21. Then, the epitaxial substrate 18 is removed.

[0168] Step D3: Etch the second epitaxial layer 19, the LED quantum well layer 9, the first epitaxial layer 20, the first electrode 10 and the connecting metal 22 to form an insulating layer 23 between adjacent light-emitting parts, and form a second electrode 14 covering the entire surface, thereby forming a plurality of independent light sources 2 including the second epitaxial layer 19, the LED quantum well layer 9, the first epitaxial layer 20, the first electrode 10 and the second electrode 14.

[0169] Step D4: A high refractive index layer 26 and a low refractive index layer 27 are sequentially deposited on the second electrode 14 by a coating process such as physical vapor deposition or atomic layer deposition, for example, to form multiple alternating TiO2 layers and SiO2 layers, or multiple alternating SiO2 layers and HfO2 layers, to form a first reflective structure 4 (second distributed Bragg reflector 25).

[0170] Step D5: A pixel definition layer 13 having openings is formed above the first reflective structure 4 (second distributed Bragg reflector 25). Then, a color conversion material is filled into the meshes of the mesh layer by spin coating, photolithography, inkjet printing, etc., to form a plurality of color conversion structures 3 corresponding one to one to the plurality of light sources 2.

[0171] Step D6: Depositing a metal material on the color conversion structure 3 by metallization to form the second reflective structure 5 (first metal film 24). The distance between the first reflective structure 4 (second DBR 25) and the second reflective structure 5 (first metal film 24) is correlated with the emission peak position of the color conversion structure 3.

[0172] Step D7: Dispose a plurality of micro lenses 15 above the second reflective structure 5 (first metal film 24 ).

[0173] 24 and 25 are schematic diagrams based on an example in which the pixel definition layer 13 is located only between adjacent color conversion structures 3. When the pixel definition layer 13 also covers the color conversion structure 3, as shown in FIG26 , which is another process flow chart of the display panel provided in an embodiment of the present application, the above-mentioned step D5 can be replaced by step D5′.

[0174] Step D5': A color conversion film 40 is formed on the first reflective structure 4 (the second distributed Bragg reflector 25) by spin coating or drop coating, and then a plurality of color conversion structures 3 corresponding to the plurality of light sources 2 are formed by photolithography or etching / lift-off. Then, a pixel definition layer 13 is formed so that part of the pixel definition layer 13 fills between adjacent color conversion structures 3 and partly covers the color conversion structures 3. At this time, the pixel definition layer 13 can also serve as an encapsulation layer and a planarization layer.

[0175] It should be noted that, for the sake of simplicity, step D1, step D2, step D3 and step D7 are omitted in FIG26 , but in its complete process flow, FIG26 should include step D1, step D2, step D3 and step D7 shown in FIG25 .

[0176] As mentioned above, setting the second reflective structure 5 as a metal film can simplify the manufacturing process of the second reflective structure 5 and reduce the difficulty of the process. Moreover, the process of forming the second reflective structure 5 causes less loss of the color conversion material. Especially when the color conversion structure 3 uses quantum dot material, the metal material and the quantum dot material have good compatibility and will not cause damage to the fluorescence quantum yield (PL QY) of the quantum dot material itself.

[0177] Moreover, in the embodiment of the present application, the thickness of the first metal film 24 can be set to be between 5 nm and 10 nm, which can significantly reduce the overall module thickness of the display panel compared to the DBR with a thickness of 100 nm to 1 um.

[0178] In one feasible embodiment, referring again to FIG. 21 , the first reflective structure 4 and the second reflective structure 5 each include a distributed Bragg reflector, each comprising a plurality of periodically alternating high-refractive index layers 26 and low-refractive index layers 27, wherein the refractive index of the high-refractive index layers 26 is greater than the refractive index of the low-refractive index layers 27. The logarithm of the period of the high-refractive index layers 26 and the low-refractive index layers 27 included in the second reflective structure 5 is smaller than the logarithm of the period of the high-refractive index layers 26 and the low-refractive index layers 27 included in the first reflective structure 4, thereby forming the resonant cavity RC1 while ensuring that light is preferentially emitted from the upper interface of the resonant cavity RC1.

[0179] In a feasible embodiment, in order to improve the effect of the resonant cavity RC1 on the target emitted light and to ensure that the interface above the resonant cavity has the advantage of light emission, the reflectivity of the first reflective structure 4 to the target emitted light is r1, and the reflectivity of the second reflective structure 5 to the target emitted light is r2. In the embodiment of the present application, r1 and r2 can be designed to be: 99%≤r1≤100%, 90%≤r2≤99%. For example, r1=99.9%, r2=90%.

[0180] In one feasible embodiment, referring to FIG1 , the target emitted light converted by the color conversion structure 3 is of the same color, wherein the distance between the first reflective structure 4 and the second reflective structure 5 is equal. Exemplarily, the color conversion structure 3 is configured to convert blue light into red light, in which case the display panel includes only red RC-MD devices. Alternatively, the color conversion structure 3 is configured to convert blue light into green light, in which case the display panel includes only green RC-MD devices.

[0181] In this structure, since the color of the light converted by the color conversion structure 3 is consistent, the emission peaks of the color conversion structure 3 at different positions tend to be consistent. At this time, the cavity lengths of the resonant cavity RC1 at different positions can be set to be equal to control the light emission direction of the target emission light of this color to the same extent.

[0182] Alternatively, in another feasible embodiment, as shown in FIG. 27 , which is a schematic diagram of another structure of a display panel provided by an embodiment of the present application, the color conversion structure 3 includes a first color conversion structure 28 and a second color conversion structure 29. The target emission light converted by the first color conversion structure 28 is a first color, and the target emission light converted by the second color conversion structure 29 is a second color. For example, the target emission light converted by the first color conversion structure 28 is a long-wavelength first color, and the target emission light converted by the second color conversion structure 29 is a short-wavelength second color. Specifically, at the location of the first color conversion structure 28, a first distance d1 is defined between the first reflective structure 4 and the second reflective structure 5, and at the location of the second color conversion structure 29, a second distance d2 is defined between the first reflective structure 4 and the second reflective structure 5. That is, the cavity length of the resonant cavity corresponding to the first color conversion structure 28 is the first distance d1, and the cavity length of the resonant cavity corresponding to the second color conversion structure 29 is the second distance d2, and the first distance d1 and the second distance d2 are different.

[0183] Exemplarily, the first color conversion structure 28 is configured to generate red light when stimulated by excitation light, and the second color conversion structure 29 is configured to generate green light when stimulated by excitation light. In this case, the display panel includes a red RC-MD device and a green RC-MD device. Furthermore, referring again to FIG. 27 , the display panel may further include a third color conversion structure 30 configured to generate blue light when stimulated by excitation light. In this case, the display panel also includes a blue RC-MD device. In one configuration, the light source 2 in the display panel is a blue micro LED. The first color conversion structure 28 is configured to generate red light when stimulated by blue light, the second color conversion structure 29 is configured to generate green light when stimulated by blue light, and the third color conversion structure 30 is configured to generate blue light when stimulated by blue light. Alternatively, the light source 2 in the display panel may be an ultraviolet LED. The first color conversion structure 28 is configured to generate red light when stimulated by ultraviolet light, the second color conversion structure 29 is configured to generate green light when stimulated by ultraviolet light, and the third color conversion structure 30 is configured to generate blue light when stimulated by ultraviolet light.

[0184] Because the colors of first color conversion structure 28 and second color conversion structure 29 differ, the emission peak positions of first color conversion structure 28 and second color conversion structure 29 differ. Therefore, the cavity length of the resonant cavity corresponding to first color conversion structure 28, i.e., the first distance, can be designed based on the emission peak position of first color conversion structure 28, and the cavity length of the resonant cavity corresponding to second color conversion structure 29, i.e., the second distance, can be designed based on the emission peak position of second color conversion structure 29. Because the emission peak positions of first color conversion structure 28 and second color conversion structure 29 differ, the first distance and the second distance differ. In this case, the cavity lengths of the resonant cavities corresponding to different color conversion structures 3 are correlated with their respective emission peak positions, thereby effectively optimizing the light output shapes of different RC-MD devices.

[0185] Furthermore, as shown in Figure 28, Figure 28 is another structural schematic diagram of the display panel provided in an embodiment of the present application. The first distance d1 is greater than the second distance d2. The display panel also includes an adjustment layer 31. The adjustment layer 31 is located between the first color conversion structure 28 and the second reflective structure 5, and the adjustment layer 31 is light-transmissive.

[0186] When the cavity length of the resonant cavity corresponding to the first color conversion structure 28 is greater than the cavity length of the resonant cavity corresponding to the second color conversion structure 29, the cavity length of the resonant cavity can be increased by adding an adjustment layer 31 in the resonant cavity corresponding to the first color conversion structure 28. At this time, the film thickness of the first color conversion structure 28 and the second color conversion structure 29 can be kept consistent, thereby weakening the difference in color conversion efficiency of different color conversion structures 3.

[0187] Of course, referring to Figure 27 again, the film thickness of the first color conversion structure 28 and the film thickness of the second color conversion structure 29 can also be designed to be different. In this case, the resonant cavities corresponding to different color conversion structures 3 can have different cavity lengths simply by adjusting the film thickness of different color conversion structures 3, and the adjustment method is simpler.

[0188] Based on the same inventive concept, the embodiment of the present application also provides a display device, as shown in Figures 29 and 30. Figure 29 is a structural schematic diagram of the display device provided by the embodiment of the present application, and Figure 30 is a schematic diagram of an application scenario of the display device provided by the embodiment of the present application. The display device 100 includes the above-mentioned display panel 101. The specific structure of the display panel 101 has been described in detail in the above-mentioned embodiment and will not be repeated here. Among them, the display device can be a near-eye display device such as AR and VR. This type of display device is essentially a micro-display projection system. In one application scenario, the display device 100 can include three display panels 101 that display red images, green images, and blue images respectively. The images generated by each of the three display panels are synthesized into one image through the optical structure 102 and projected onto the screen 200 to achieve a projection effect.

[0189] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

[0190] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A display panel, characterized in that: include: Driver backplane; A light source, located on one side of the driving backplane, for emitting excitation light; A color conversion structure, located on a side of the light source facing away from the driving backplane, for converting the excitation light into target emission light; A first reflective structure, located on a side of the color conversion structure facing the driving backplane, for reflecting the target emitted light; A second reflective structure, located on a side of the color conversion structure facing away from the driving back plate, the second reflective structure being used to reflect the excitation light and the target emission light; The reflectivity of the second reflective structure to the target light is lower than the reflectivity of the first reflective structure to the target light.

2. The display panel according to claim 1, characterized in that: The first reflective structure is located between the light source and the color conversion structure.

3. The display panel according to claim 2, characterized in that: The first reflective structure is also used to transmit the excitation light.

4. The display panel according to claim 2, characterized in that: The first reflective structure is also used to reflect the excitation light; The light source includes an LED quantum well layer and a first electrode, wherein the first electrode is located on a side of the LED quantum well layer close to the driving backplane, and the reflectivity of the first reflective structure to the excitation light is lower than the reflectivity of the first electrode to the excitation light.

5. The display panel according to claim 1, characterized in that: The light source comprises an LED quantum well layer and a first electrode, wherein the first electrode is located on a side of the LED quantum well layer close to the driving backplane; The first reflective structure is multiplexed with the first electrode.

6. The display panel according to claim 5, characterized in that: The first electrode comprises a sub-reflection portion and a sub-connection portion, the sub-reflection portion is located between the sub-connection portion and the LED quantum well layer, and the sub-connection portion is bonded to the driving backplane; The reflectivity of the sub-reflecting portion to the light emitted by the target is greater than the reflectivity of the sub-connecting portion to the light emitted by the target.

7. The display panel according to claim 1, characterized in that: The display panel comprises a plurality of the color conversion structures, one of the color conversion structures corresponds to one of the light sources; The display panel further includes a pixel definition layer, at least a portion of which is located between adjacent color conversion structures.

8. The display panel according to claim 7, characterized in that: The pixel definition layer is also located on a side of the color conversion structure facing away from the driving backplane, the pixel definition layer covers the color conversion structure, and the second reflective structure is located on a side of the pixel definition layer facing away from the driving backplane.

9. The display panel according to claim 7, characterized in that: The light source comprises an LED quantum well layer and a second electrode, wherein the second electrode is located on a side of the LED quantum well layer facing away from the driving backplane; The pixel definition layer and the first reflective structure and / or the second reflective structure in contact with the pixel definition layer all have conductive properties, and the pixel definition layer is also electrically connected to the second electrode.

10. The display panel according to claim 1, characterized in that: In a direction perpendicular to the plane where the display panel is located, the color conversion structure covers the plurality of light sources.

11. The display panel according to claim 1, characterized in that: At least one of the first reflective structure and the second reflective structure includes a distributed Bragg reflector, and / or at least one of the first reflective structure and the second reflective structure includes a metal material.

12. The display panel according to claim 1, characterized in that: The first reflective structure and the second reflective structure respectively include a distributed Bragg reflector, and the distributed Bragg reflector includes a plurality of high refractive index layers and low refractive index layers that are alternately arranged in a periodic manner; The period logarithm of the high refractive index layer and the low refractive index layer included in the second reflective structure is smaller than the period logarithm of the high refractive index layer and the low refractive index layer included in the first reflective structure.

13. The display panel according to claim 1, characterized in that: The reflectivity of the first reflective structure to the target light is r1, 99%≤r1≤100%, and the reflectivity of the second reflective structure to the target light is r2, 90%≤r2≤99%.

14. The display panel according to claim 1, characterized in that: The target emission light converted by the color conversion structure is of the same color; Wherein, the distance between the first reflective structure and the second reflective structure is equal.

15. The display panel according to claim 1, characterized in that: The color conversion structure includes a first color conversion structure and a second color conversion structure, the target emission light converted by the first color conversion structure is a first color, and the target emission light converted by the second color conversion structure is a second color; Wherein, at the location of the first color conversion structure, there is a first distance between the first reflective structure and the second reflective structure, and at the location of the second color conversion structure, there is a second distance between the first reflective structure and the second reflective structure, and the first distance is different from the second distance.

16. The display panel according to claim 15, characterized in that: The first distance is greater than the second distance, and the display panel further includes an adjustment layer, and the adjustment layer is located between the first color conversion structure and the second reflection structure.

17. A display device, characterized in that: Comprising the display panel as claimed in any one of claims 1 to 16.

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