In some embodiments, in the direction perpendicular to the bearing surface of the base substrate 11, the light conversion layer 2 includes a layer of the first micro-mirror structure.

The light-emitting layer includes a plurality of light-emitting units arranged in an array, and each of the light-emitting units includes a first electrode in the first electrode layer 13, a light-emitting portion in the light-emitting material layer 14, and a second electrode in the second electrode layer 15. The plurality of light-emitting units are in one-to-one correspondence to the plurality of sub-pixels. That is, each of the sub-pixels includes one of the light-emitting units. For the light conversion unit and the light-emitting unit that are disposed within the same sub-pixel, an orthographic projection of the light conversion unit on the bearing surface of the base substrate 11 is at least partially overlapped with an orthographic projection of the light-emitting unit on the bearing surface of the base substrate 11. In some embodiments, the plurality of light-emitting units emit blue light under the control of the driver circuit layer 12. The blue light, after passing through the red light conversion unit 21, the green light conversion unit 22, and the blue light conversion unit 23, correspondingly generates red, green, and blue light, which respectively correspond to the first sub-pixel p1, the second sub-pixel p2, and the third sub-pixel p3, such that a color display is realized.

In some embodiments, the first electrode layer 13 is an anode layer and the second electrode layer 15 is a cathode layer; alternatively, the first electrode layer 13 is a cathode layer and the second electrode layer 15 is an anode layer.

The driver circuit layer 12 includes a plurality of pixel circuits. Each of the pixel circuits includes electronic devices such as thin film transistors (TFT) and capacitances (C). The TFT includes a switch TFT and a driver TFT. In some embodiments, the pixel circuit is a 2T1C structure including two TFTs (a switch TFT and a driver TFT) and a capacitor; of course, the pixel circuit includes more than two TFTs (a plurality of switch TFTs and a driver TFT) and at least one capacitor. The pixel circuit must include a driver TFT, and the driver TFT is connected to the light-emitting unit.

In the experiment process, it was found that not only blue light excites red quantum dots of red light-emitting particles to emit red light, but green light also excites red light-emitting particles of red quantum dots to emit red light. That is, for a red light conversion unit and an adjacent green light conversion unit, in the case that only the green light conversion unit is controlled to emit light, the red light conversion unit is interfered by the large-angle green light emitted from the adjacent green light conversion unit and is mistakenly excited to emit red light, generating a problem of color crosstalk.

In some embodiments of the present disclosure, as illustrated in FIG. 2, to ameliorate the problem of color crosstalk, an area of an orthographic projection of the red light conversion unit 21 on the bearing surface of the substrate 11 is minimized, and an area of an orthographic projection of the green light conversion unit 22 on the bearing surface of the substrate 11 is similar to an area of an orthographic projection of the blue light conversion unit 23 on the bearing surface of the substrate 11, such that a distance between the red light conversion unit 21 and the green light conversion unit 22, and a distance between the red light conversion unit 21 and the blue light conversion unit 23 are increased, and thus the problem of color crosstalk is improved. Meanwhile, for the light extraction efficiency of the red light conversion unit 21, although the luminance efficiency of the red light is reduced due to the minimum area of the orthographic projection of the red light conversion unit 21 on the bearing surface of the base substrate 11, the light extraction efficiency of the red light is high because of the plurality of first micro-mirror structures arranged around the red light conversion unit 21.

In some embodiments, the light conversion layer 2 further includes a first isolation structure 25. The first isolation structure 25 is in the light conversion layer 2, and an orthographic projection of the first isolation structure 25 on the bearing surface of the base substrate 11 covers orthographic projections of the plurality of micro-mirror structures 20 on the bearing surface of the base substrate 11.

In some embodiments, the first isolation structure 25 is made of a light-absorbing material, such as a black organic material.

In some other embodiments, as illustrated in FIG. 3, FIG. 3 is a schematic diagram of a film layer structure of another display panel according to some embodiments of the present disclosure. In the case that the area of the orthographic projection of the red light conversion unit 21 on the bearing surface of the base substrate 11 is not reduced, the distance between the red light conversion unit 21 and the green light conversion unit 22 and the distance between the red light conversion unit 21 and the blue light conversion unit 23 are increased, and the plurality of micro-mirror structures 20 are arranged around the red light conversion unit 21, such that the light extraction efficiency of the red light of the display panel is further improved.

FIG. 4 is a top-view schematic diagram of a micro-mirror structure according to some embodiments of the present disclosure. FIG. 5 is a top-view schematic diagram of another micro-mirror structure according to some embodiments of the present disclosure. As illustrated in FIG. 4, the orthographic projection of the micro-mirror structure 20 on the bearing surface of the base substrate 11 is in a hexagonal shape; or, as illustrated in FIG. 5, the orthographic projection of the micro-mirror structure 20 on the bearing surface of the base substrate 11 is in an octagonal shape; or the orthographic projection of the micro-mirror structure 20 on the bearing surface of the base substrate 11 is in a circular shape. The plurality of first micro-mirror structures around the red light conversion unit 21 are close-packed as far as possible. That is, gaps between the plurality of micro-mirror structures are minimized as much as possible. The close-packed arrangement allows as many first micro-mirror structures as possible to be placed, such that the light extraction efficiency is improved as much as possible.

FIG. 6 is a schematic diagram of a three-dimensional structure of a micro-mirror structure according to some embodiments of the present disclosure. As illustrated in FIG. 6, the description is given using a scenario where the orthographic projection of the micro-mirror structure on the bearing surface of the base substrate 11 is in a hexagonal shape as an example, the micro-mirror structure 20 has a curved top surface, and six side surfaces perpendicular to the bearing surface of the base substrate 11. That is, the micro-mirror structure 20 has a curvature to protrude towards a direction away from the base substrate 11.

For the micro-mirror structures of different shapes, a hemispherical micro-mirror structure has the best light extraction effect, and the orthographic projection of the hemispherical micro-mirror structure on the bearing surface of the base substrate 11 is in a circular shape. However, a filling rate is lower in the case that the plurality of hemispherical micro-mirror structures are close-packed. For the micro-mirror structure having a rectangular orthographic projection on the bearing surface of the substrate 11, the filling rate is high in the case that the plurality of micro-mirror structures are close-packed, but the light extraction efficiency is low. Compared to the above two micro-mirror structures, the micro-mirror structure with a hexagonal or octagonal orthographic projection is more similar to the hemispherical micro-mirror structure, and has a higher light extraction efficiency. At the same time, the orthographic projection of hexagonal or octagonal shape achieves a high filling rate when the plurality of micro-mirror structures are close-packed, and thus the red light efficiency is further improved. Herein, the filling rate is the rate of the sum of the areas of the orthographic projections of the plurality of micro-mirror structures on the bearing surface of the base substrate 11 to a total area of a region in which the micro-mirror structures are provided, at a top-view angle of FIG. 4 or FIG. 5. Thus, the smaller the gap between the micro-mirror structures, the greater the fill rate.

Considering the two factors of the shape of the micro-mirror structure and the filling rate together, it is selected that the orthographic projection on the bearing surface of the base substrate 11 is in a hexagonal shape and the adjacent hexagons share the same side to improve the light extraction efficiency.

FIG. 7 is a side-view schematic diagram of a micro-mirror structure according to some embodiments of the present disclosure, as illustrated in FIG. 7, the micro-mirror structure 20 includes a reflection portion 201 and a lens portion 202 that are successively stacked. The reflection portion 201 is proximal to the base substrate 11. The reflection portion 201 is capable of reflecting light with any angle not just a large angle, and thus light extraction is further increased. In some embodiments, the reflection portion 201 is made of a metallic material, such as copper, silver, aluminum, and other materials. In some embodiments, the lens portion 202 is made of glass.

In some embodiments, the reflection portion 201 is in the shape of a hemisphere (as illustrated in FIG. 7), a column, a dome, a prism, a cone, or a prism. All of the reflection portions 201 of these shapes achieve the purpose of reflecting the light back to the region of the red light conversion unit.

In some embodiments, as illustrated in FIG. 7, a thickness h of the micro-mirror structure 20 ranges from 1 m to 3 μm.

In some embodiments of the present disclosure, the plurality of micro-mirror structures 20 further include at least one type of a plurality of second micro-mirror structures surrounding the green light conversion unit 22 and a plurality of third micro-mirror structures surrounding the blue light conversion unit 23. For any red light conversion unit 21 and any green light conversion unit 22, the number of second micro-mirror structures surrounding the green light conversion unit 22 is less than the number of first micro-mirror structures surrounding the red light conversion unit 21. For any red light conversion unit 21 and any blue light conversion unit 23, the number of third micro-mirror structures surrounding the blue light conversion unit 23 is less than the number of first micro-mirror structures surrounding the red light conversion unit 21. By providing a small number of micro-mirror structures surrounding the blue light conversion unit and the green light conversion unit, the color balance is achieved.

In some embodiments, the plurality of second micro-mirror structures are provided around the green light conversion unit 22, and the plurality of third micro-mirror structures are provided around the green light conversion unit 22. Compared to the plurality of first micro-mirror structures, as illustrated in FIG. 4 or FIG. 5, in a direction parallel to the base substrate, the plurality of first micro-mirror structures 20 surrounding one of the red light conversion units are approximately divided into a plurality of circles; using the plurality of second micro-mirror structures surrounding one of the green light conversion units as an example, in the direction parallel to the base substrate, one of the green light conversion units has only one circle of the second micro-mirror structures.

In some embodiments of the present disclosure, the plurality of micro-mirror structures 20 include only the plurality of first micro-mirror structures; alternatively, the plurality of micro-mirror structures 20 include only the plurality of first micro-mirror structures and the plurality of second micro-mirror structures; alternatively, the plurality of micro-mirror structures 20 include only the plurality of first micro-mirror structures and the plurality of third micro-mirror structures; alternatively, the plurality of micro-mirror structures 20 include the plurality of first micro-mirror structures, the plurality of second micro-mirror structures, and the plurality of third micro-mirror structures. For a light conversion unit, the more the number of surrounding micro-mirror structures, the higher the light extraction efficiency of the light conversion unit. For consideration of the color balance, different numbers of second micro-mirror structures and third micro-mirror structures are provided around the green light conversion unit or the blue light conversion unit.

In some embodiments, the plurality of micro-mirror structures 20 surrounding the same light conversion unit have different sizes and different shapes.

In some embodiments, orthographic projections of the plurality of first micro-mirror structures are overlapped with the orthographic projection on the bearing surface of the base substrate 11 of the first light conversion unit being surrounded. In some embodiments, an edge of the first light conversion unit overlaps a portion of the first micro-mirror structures.

In other embodiments, orthographic projections of the plurality of first micro-mirror structures are not overlapped with the orthographic projection on the bearing surface of the base substrate 11 of the first light conversion unit being surrounded, such as the structure illustrated in FIG. 3.

FIG. 8 is a schematic diagram of a film layer structure of another display panel according to some embodiments of the present disclosure. As illustrated in FIG. 8, to improve the problem of color crosstalk while increasing the light extraction, on the basis of providing the plurality of layers of micro-mirror structures 20, the first isolation structure 25 is in the light conversion layer 2 and the first isolation structure 25 is made of a material with a refractive index that is less than the refractive index of the material of the light conversion unit. The refractive index of the material of the first isolation structure 25 is less than the refractive index of the light conversion unit. That is, the material of the first isolation structure 25 is an optically thinner medium with respect to the light conversion unit, and the light conversion unit is an optically denser medium with respect to the material of the first isolation structure 25. Therefore, light being incident to an interface of the light conversion unit and the first isolation structure 25 is equivalent to light being incident from the optically denser medium to the optically thinner medium, and in the case that the incident angle satisfies the total reflection condition, the total reflection occurs, and the light returns to an interior of the light conversion unit from the interface of the light conversion unit and the first isolation structure 25. Thereby, the total reflection of light is realized and the problem of color crosstalk is improved without the need to arrange an optical structure at the interface of the light conversion unit and the first isolation structure 25. At the same time, compared to a light-absorbing structure, which absorbs the large-angle light generated within the respective light conversion units and thus leads to the problem of low optical power, the light extraction is increased due to the fact that the first isolation structure 25 fully reflects the large-angle light within the respective light conversion units back to the corresponding region.

In some embodiments, in the direction perpendicular to the bearing surface of the base substrate 11, the light conversion layer 2 includes a layer of first micro-mirror structure and a low refractive index material. The low refractive index material fills in the gaps of the plurality of first micro-mirror structures until the region including the first micro-mirror structures is filled to be flush with the light conversion unit.

As illustrated in FIG. 8, the display panel further includes a color film layer 3. The color film layer 3 is disposed on a side, distal from the base substrate 11, of the light conversion layer 2. The color film layer 3 includes a plurality of color resist blocks. The plurality of color resist blocks are in one-to-one correspondence to the plurality of light conversion units. The plurality of color resist blocks are separated from each other by a light-absorbing material such as a black matrix.

FIG. 9 is a schematic diagram of a film layer structure of another display panel according to some embodiments of the present disclosure. Compared to the embodiments illustrated in FIG. 8, in the embodiments illustrated in FIG. 9, the display panel further includes a color film layer 3, the color film layer 3 being disposed on a side, distal from the base substrate 11, of the light conversion layer 2. The color film layer 3 includes a plurality of color resist blocks and a second isolation structure 31. The plurality of color resist blocks are in one-to-one correspondence to the plurality of light conversion units. The second isolation structure 31 is disposed between adjacent color resist blocks, and the first isolation structure 25 and the second isolation structure 31 are formed as a one-piece structure. The one-piece structure herein means that the first isolation structure 25 and the second isolation structure are two parts of an integral structure, and the first isolation structure 25 and the second isolation structure are made of the same material. The connected first isolation structure 25 and the second isolation structure 31 further improve the color crosstalk, and at the same time increase the light extraction by always reflecting, in a direction from close to the light conversion unit to away from the light conversion unit, the large-angle light back into the corresponding light conversion unit and color resist region until the light exits out of the color film layer.

In some embodiments, the first isolation structure 25 and the second isolation structure 31 are made of organic materials, such as polyimide, polymethylmethacrylate, and the like.

FIG. 10 is a schematic diagram of a film layer structure of another display panel according to some embodiments of the present disclosure. As illustrated in FIG. 10, compared to the display panel illustrated in FIG. 9, the light conversion layer 2 further includes a reflection structure 26. The reflection structure 26 is in the first isolation structure 25 and surrounds the light conversion unit. The reflection structure 26 further improves the phenomenon of color crosstalk between adjacent two light conversion units, and the reflection structure 26 also provides a better total reflection of the large-angle light.

In some embodiments, as illustrated in FIG. 10, a size of the reflection structure 26 is the same as a size of the light conversion unit in the direction perpendicular to the bearing surface of the base substrate.

In some other embodiments, a height of the reflection structure 26 is also slightly higher or slightly lower than a height of the light conversion unit. In some embodiments, an absolute value of a height difference between the reflection structure 26 and the light conversion unit ranges from 0 to 2.5 μm.

In some embodiments, the reflection structure 26 is made of a metallic material, such as copper, silver, aluminum, and other metallic materials.

It should be noted that the reflection structure 26 is provided in the display panel illustrated in FIG. 8.

In some embodiments, the light conversion layer 2 is prepared directly on the package layer 16.

In some other embodiments, the display panel further includes a first adhesive layer. The first adhesive layer is disposed between the color film layer 3 and the light conversion layer 2. The first adhesive layer is made of an organic adhesive material to adhere the color film layer and to the light conversion layer.

In some embodiments, the display panel further includes a second adhesive layer. The second adhesive layer is disposed between the light conversion layer 2 and the package layer 16. The second adhesive layer is made of an organic adhesive material to adhere the light conversion to the package layer.

In some embodiments of the present disclosure, the light conversion unit includes a plurality of scattering particles, and the scattering particles are configured to increase the optical path of the light emitted from the light-emitting unit and increase the absorption of the blue light by the light conversion unit. FIG. 11 is a schematic structural diagram of a scattering particle according to some embodiments of the present disclosure. As illustrated in FIG. 11, the scattering particle 24 includes a core structure 241 and a shell structure 242 surrounding the core structure 241. The shell structure 242 is an unenclosed structure with holes therein.

The light emitted from the light-emitting layer is reflected between the core structure 241 and the shell structure 242 of the scattering particle 24 after entering the light conversion unit, and the light path is increased, which increases the absorption of the light emitted from the light-emitting layer by the light conversion unit, and improves the conversion efficiency of the light conversion layer, such that the light extraction rate of the light conversion unit including the red light conversion unit and the green light conversion unit is further improved.

In some embodiments of the present disclosure, although the blue light conversion unit does not include the quantum dot light-emitting particles, it still includes the scattering particles. In this way, the viewing angle of the product is improved, the uniformity of the doping of the light conversion layer is increased, and the manufacturing process is simplified.

In some embodiments, as illustrated in FIG. 11, a diameter d1 of the scattering particle 24 ranges from 10 nm to 300 nm, a diameter d2 of the core structure 241 ranges from 2 nm to 8 nm, and a thickness d3 of the shell structure 242 ranges from 10 nm to 20 nm. By defining the size of the scattering particle to be within the above range, on the premise of satisfying the stable manufacturing as much as possible, the scattering particles will not be too small to agglomerate easily, and will not be too large to cause poor scattering effect.

In some embodiments, the shell structure 242 is made of metal oxide, nitride, fluoride, or nitrogen oxide.

The core structure 241 is made of titanium, tantalum, zirconium, niobium, aluminum, silicon, magnesium, iridium, yttrium, ytterbium, indium, tungsten, molybdenum, vanadium, nickel, silver, copper, gold, or an alloy. The material, such as metal oxide, nitride, fluoride, or nitrogen oxide, is etched by organic acidic or alkaline solvents to form an unenclosed structure with holes therein. The metal oxide, nitride, fluoride, or nitrogen oxide, and materials such as titanium, tantalum, and alloys, are able to reflect light well.

In some embodiments, the display panel according to the present disclosure includes the scattering particles and does not include the micro-mirror structure 20, the first isolation structure 25, the second isolation structure 31, and the reflection structure 26 as described above.

In some other embodiments, the display panel according to the present disclosure includes the scattering particles and the plurality of micro-mirror structures 20 (as illustrated in FIG. 2 or FIG. 3).

In some other embodiments, the display panel according to the present disclosure includes the scattering particles and the first isolation structure 25 (as illustrated in FIG. 8); or the display panel according to the present disclosure includes the scattering particles, the first isolation structure 25, and the second isolation structure 31 (as illustrated in FIG. 9); or the display panel according to the present disclosure includes the scattering particles, the first isolation structure 25, the second isolation structure 31, and the reflection structure 26 (as illustrated in FIG. 10).

In some other embodiments, the display panel according to the present disclosure includes the scattering particles, the micro-mirror structure 20, and the first isolation structure 25 (as illustrated in FIG. 8); or the display panel according to the present disclosure includes the scattering particles, the micro-mirror structure 20, the first isolation structure 25, and the second isolation structure 31 (as illustrated in FIG. 9); or the display panel according to the present disclosure includes the scattering particles, the micro-mirror structure 20, the first isolation structure 25, the second isolation structure 31, and the reflection structure 26 (as illustrated in FIG. 10).

In some embodiments of the present disclosure, the red light conversion unit and the green light conversion unit include a plurality of organic nanoparticles. The organic nanoparticles are connected, via organic groups on the organic nanoparticles, to the quantum dot light-emitting particles in the light conversion unit in which they are disposed.

The higher the concentration of the quantum dot light-emitting particles, the higher the conversion rate of light. However, quenching occurs in the case that the concentration of the quantum dot light-emitting particles is too high. After the organic nanoparticles are added, the organic nanoparticles surround the quantum dot light-emitting particles, and thus the quantum dot light-emitting particles are less likely to agglomerate. In this way, the problem of agglomeration and quenching of the quantum dot light-emitting particles after too many of the quantum dot light-emitting particles are added, such that the maximum addition concentration of the quantum dot light-emitting particles is improved, and thus the luminance of the product is improved.

In some embodiments, the quantum dot light-emitting particle is made of at least one compound among CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, HgS, HgTe, GaN, GaAs, InP, and InAs.

In some embodiments, the organic nanoparticle has the following structural formula.

[Image Omitted]

The organic group A on the organic nanoparticle and used to connect to the quantum dot light-emitting particle includes any one of NC—, HOOC—, HRN—, O═P(R)₂—, POOOH—, RS—, and RSS—. The R group includes any one of a hydrogen atom, a saturated carbon-chain with the number of carbon atoms from 1 to 10, and an unsaturated carbon-chain with the number of carbon atoms from 1 to 10.

Any of the X₁group, the X₂group, and the X₃group includes any one of a hydrogen atom, an aryl group, a phenyl group, a halogen, —CH₃, —(CH₂)a-CH₃, —COOH, —COOCH₃, and —CH═CH₂, wherein a is an integer greater than or equal to one.

The E group includes any one of a hydrogen atom, a halogen, a hydroxyl group, a carboxyl group, a carboxylic acid, an ester, a mercapto group, an amine group, a formyl group, —SO₂NH₂, —NHNH₂, a saturated carbon-chain with the number of carbon atoms from 1 to 30, and an unsaturated carbon-chain with the number of carbon atoms from 1 to 10.

The D group includes any one of a hydrogen atom, a halogen, a hydroxyl group, a carboxyl group, a carboxylic acid, an ester, a mercapto group, an amine group, a formyl group, —SO₂NH₂, —NHNH₂, a saturated carbon-chain with the number of carbon atoms from 1 to 30, and an unsaturated carbon-chain with the number of carbon atoms from 1 to 10.