Display substrate and display device

Abstract

A display substrate and a display device. The display substrate comprises a plurality of light-emitting diode chips, each light-emitting diode chip comprising a plurality of light-emitting units respectively emitting light of different colors, each light-emitting unit comprising a first electrode, a light-emitting layer, a substrate and a second electrode, the substrate and the second electrode being respectively located on two sides of the light-emitting layer. In each light-emitting diode chip, the plurality of light-emitting units share the substrate and the first electrode, the light-emitting layers of the plurality of light-emitting units emit light of the same color, and at least one light-emitting unit further comprises a first color conversion layer located on the side of the substrate away from the light-emitting layer, to convert the first color light emitted by the light-emitting layer into second color light. In the display substrate of the present disclosure, each light-emitting diode chip comprises at least two light-emitting units of different colors, the high pixel density requirement can be achieved, and the plurality of light-emitting units share one first electrode, which can improve the light-emitting area of the light-emitting unit.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a display substrate and a display device. BACKGROUND

[0002] At present, inorganic light-emitting display devices, such as mini light-emitting diodes (Mini LED) or micro light-emitting diodes (Micro LED), are increasingly widely used. The LED display industry chain involves display backplanes, LED devices, and die bonding transfer technology. SUMMARY

[0003] The present disclosure relates to a display substrate and a display device.

[0004] The present disclosure relates to a display substrate and a display device.

[0005] For example, in an embodiment of the present disclosure, each light-emitting unit further comprises a first contact pad and a second contact pad arranged in the same layer, the first contact pad is connected with the first electrode, and the second contact pad is connected with the second electrode; each light-emitting diode chip comprises a first color light-emitting unit, a second color light-emitting unit, and a third color light-emitting unit, the first color light-emitting unit is configured to emit the first color light, the second color light-emitting unit further comprises the first color conversion layer located on the side of the substrate away from the light-emitting layer, and emits the second color light, and the third color light-emitting unit further comprises a second color conversion layer located on the side of the substrate away from the light-emitting layer, to convert the first color light emitted by the light-emitting layer into third color light.

[0006] For example, in an embodiment of the present disclosure, in each light-emitting diode chip, the connecting line of the geometric centers of the light-emitting regions of the first color light-emitting unit, the second color light-emitting unit, and the third color light-emitting unit forms a first triangle, and the ratio of the shortest distances between the edges of the light-emitting regions of different color light-emitting units is 0.6-1.5.

[0007] For example, in the embodiments of the present disclosure, the light emitting regions of the plurality of light emitting units in each light emitting diode chip are distributed in a rectangular region, and the light emitting regions of the first color light emitting units, the second color light emitting units and the third color light emitting units are respectively located at three right angles of the rectangular region.

[0008] For example, in the embodiments of the present disclosure, in each light emitting diode chip, the second contact pads of the first color light emitting units, the second contact pads of the second color light emitting units and the second contact pads of the third color light emitting units are respectively distributed at the three right angles of the rectangular region, and the first contact pad is located at the fourth right angle of the rectangular region.

[0009] For example, in the embodiments of the present disclosure, the first triangle is an acute triangle.

[0010] For example, in the embodiments of the present disclosure, in each light emitting diode chip, the geometric centers of the second contact pads of the first color light emitting units, the second contact pads of the second color light emitting units and the second contact pads of the third color light emitting units are connected to form a second triangle, and at least part of the first contact pad is located in the second triangle.

[0011] For example, in the embodiments of the present disclosure, the area of the light emitting region of the second color light emitting unit and the area of the light emitting region of the third color light emitting unit are both greater than the area of the light emitting region of the first color light emitting unit.

[0012] For example, in the embodiments of the present disclosure, the plurality of light emitting diode chips are arranged in an array along a first direction and a second direction, and the pitch of the plurality of light emitting diode chips along at least one of the first direction and the second direction is not greater than 400 microns.

[0013] For example, in the embodiments of the present disclosure, the side of the substrate away from the light emitting layer is provided with a plurality of grooves.

[0014] For example, in the embodiments of the present disclosure, the depth of at least one groove is greater than 10 microns.

[0015] For example, in the embodiments of the present disclosure, each light emitting unit is provided with one groove, the groove overlaps the light emitting layer in each light emitting unit, and the inner side wall of at least one groove is provided with a light shielding layer; the first color conversion layer is arranged in the groove of the second color light emitting unit, and the second color conversion layer is arranged in the groove of the third color light emitting unit.

[0016] For example, in the embodiments of the present disclosure, a transparent filling layer is arranged in the bottom of the groove of at least one of the second color light emitting unit and the third color light emitting unit.

[0017] For example, in embodiments of the present disclosure, a spacing between grooves of adjacent light emitting units is provided with a blocking portion away from a side of the light emitting layer, and a material of the blocking portion comprises a hydrophobic material.

[0018] For example, in embodiments of the present disclosure, at least part of the plurality of grooves is provided between adjacent light emitting units, and at least an inner side wall of each groove is provided with a light shielding material.

[0019] For example, in embodiments of the present disclosure, a side of the substrate away from the light emitting layer is provided with a pixel defining portion comprising a plurality of openings to define a plurality of light emitting regions of the plurality of light emitting units, and an opening of the second color light emitting unit is provided with the first color conversion layer, and an opening of the third color light emitting unit is provided with the second color conversion layer.

[0020] For example, in embodiments of the present disclosure, at least one groove is filled with the light shielding material, and at least part of the pixel defining portion is provided in a stacked manner with the light shielding material.

[0021] For example, in embodiments of the present disclosure, in each light emitting diode chip, the light emitting regions of the plurality of light emitting units are arranged along a third direction, and the second contact pad is located on a side of the light emitting regions of the plurality of light emitting units in a fourth direction, and the third direction and the fourth direction intersect.

[0022] For example, in embodiments of the present disclosure, in each light emitting diode chip, a shortest distance between edges of light emitting regions of adjacent light emitting units is not greater than 50 microns.

[0023] For example, in embodiments of the present disclosure, the plurality of light emitting diode chips are arranged in an array along a first direction and a second direction, and a pitch of the plurality of light emitting diode chips along at least one of the first direction and the second direction is not greater than 300 microns.

[0024] For example, in embodiments of the present disclosure, materials of the first color conversion layer and the second color conversion layer comprise quantum dot materials or fluorescent materials.

[0025] For example, in embodiments of the present disclosure, the first color light emitting unit is a blue light emitting unit, one of the second color light emitting unit and the third color light emitting unit is a red light emitting unit, and the other is a green light emitting unit.

[0026] At least one embodiment of the present disclosure provides a display device comprising any of the display substrates described above. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings of the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description only relate to some embodiments of the present disclosure and not limit the present disclosure.

[0028] Figure 1 A current density and luminous efficiency relationship diagram of red light emitting diode chips, green light emitting diode chips and blue light emitting diode chips in full color display;

[0029] Figure 2 A luminous efficiency change with temperature relationship diagram of red light emitting diode chips and green light emitting diode chips;

[0030] Figure 3 A plane schematic diagram of a display substrate provided according to an embodiment of the present disclosure;

[0031] Figure 4 A plane distribution schematic diagram of a plurality of light emitting units in a light emitting diode chip provided according to an embodiment of the present disclosure; Figure 3 A partial cross-sectional structure schematic diagram of the display substrate shown in FIG. 8 along the AA' line;

[0032] Figure 5 A partial cross-sectional structure schematic diagram of a second color light emitting unit and a third color light emitting unit;

[0033] Figure 6 A plane distribution schematic diagram of a plurality of light emitting units in a light emitting diode chip provided according to an embodiment of the present disclosure; Figure 7 A plane distribution schematic diagram of a plurality of light emitting units in a light emitting diode chip provided according to an embodiment of the present disclosure;

[0034] Figure 8 A plane distribution schematic diagram of a plurality of light emitting units in a light emitting diode chip provided according to another embodiment of the present disclosure; Figure 9 A plane distribution schematic diagram of a plurality of light emitting units in a light emitting diode chip provided according to another embodiment of the present disclosure;

[0035] Figure 10 A plane distribution schematic diagram of a plurality of light emitting units in a light emitting diode chip provided according to another embodiment of the present disclosure;

[0036] Figures 11 to 16 A partial process flow diagram for forming a light emitting diode chip;

[0037] Figure 17 A partial cross-sectional structure schematic diagram of a display substrate provided according to an embodiment of the present disclosure;

[0038] Figure 18 A partial cross-sectional structure schematic diagram of a display substrate provided according to an embodiment of the present disclosure;

[0039] Figure 19 A partial cross-sectional structure schematic diagram of a display substrate provided according to an embodiment of the present disclosure;

[0040] Figure 20 As Figures 17 to 19 A planar arrangement diagram of light emitting regions of a plurality of light emitting units in any of the display substrates shown;

[0041] Figure 21 A partial cross-sectional structure diagram of a display substrate provided according to an embodiment of the present disclosure;

[0042] Figure 22 A structure diagram for forming a groove in a sapphire layer of a light emitting diode chip and forming a color conversion layer in the groove; and

[0043] Figure 23 A structure diagram for forming a groove in a sapphire layer of a light emitting diode chip and forming a light shielding material in the groove. DETAILED DESCRIPTION

[0044] To make the objectives, technical solutions and advantages of the embodiments of the present disclosure clearer, the technical solutions of the embodiments of the present disclosure will be described clearly and completely below with reference to the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are some, but not all, of the embodiments of the present disclosure. Based on the described embodiments of the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present disclosure.

[0045] Unless otherwise defined, technical terms or scientific terms used in the present disclosure shall have the ordinary meaning understood by one of ordinary skill in the art to which the present disclosure pertains. The terms "first", "second", and similar terms used in the present disclosure do not denote any order, quantity, or importance, but are used to distinguish different components. The terms "include" or "contain" and similar terms mean that the elements or objects before the terms encompass the elements or objects listed after the terms and their equivalents, and do not exclude other elements or objects.

[0046] In the research, the inventors of the present application found that in full-color display (such as color display realized by cooperation of red sub-pixels, blue sub-pixels and green sub-pixels), the limitations of the epitaxial wafer material (such as aluminum gallium indium phosphide AlGaInP) of the red light emitting diode chip, for example, more material defects, severe lattice vibration, larger surface recombination rate resulting in increased non-radiative recombination, etc., will result in lower efficiency of the red light emitting diode chip.

[0047] Figure 1 A current density and luminous efficiency relationship diagram of red (R) light emitting diode chips, green (G) light emitting diode chips and blue (B) light emitting diode chips in full-color display, and Table 1 is a numerical relationship table of current density and luminous efficiency of different color light emitting diode chips in two groups of light emitting diode chips. As Figure 1As shown in Table 1, with a display panel brightness of 2000 nits as the baseline, a package transmittance (light transmittance after the display panel is packaged) of 60%, an RGB white balance ratio of 3:6:1, and an aperture ratio of 2% for each pixel, the efficiency of the red light-emitting diode (LED) chip in the display panel is lower than that of the green and blue LED chips. Furthermore, the red LED chip requires a larger driving current density, approximately five times that required by the green or blue LED chips, which will increase the power consumption of the display panel.

[0048] Table 1

[0049] Light emitting diode chip set 1 Light emitting diode chip set 2 R light emitting diode chip current density 613.91 (mA / cm 2 )]]> 391.56 (mA / cm 2 ) G light emitting diode chip current density 231.83 (mA / cm 2 )]]> 78.85 (mA / cm 2 )]]> B light emitting diode chip current density 118.86 (mA / cm 2 )]]> 77.99 (mA / cm 2 )]]> R luminous efficiency 8.14 (cd / A) 12.77 (cd / A) G luminous efficiency 43.13 (cd / A) 126.81 (cd / A) B luminous efficiency 14.01 (cd / A) 21.37 (cd / A)

[0050] Figure 2 The graph shows the relationship between the brightness percentage of red and green LED chips and temperature. Table 2 shows the relationship between the brightness percentage of the red LED chip and temperature. Figure 2 As shown in Table 2, temperature changes can affect the luminous efficiency of LED chips during use. For example, when an LED chip is heated, its nonradiative recombination ratio increases, resulting in a decrease in luminous efficiency.

[0051] like Figure 2 As shown in Table 2, the brightness percentage of the red LED chip decreases sharply with rising temperature, especially at 50℃, where it drops to around 40%. During normal display operation, the temperature of a typical display panel reaches approximately 50℃. At this temperature, the luminous efficiency of the red LED chip is low, severely impacting the display quality. Abnormal display of the red LED chip when the display panel shows a white image can also cause white balance anomalies. To compensate for the red light brightness in the display panel, the current to the red LED chip needs to be increased, which increases the power consumption of the display panel. Therefore, due to the relatively poor stability of the red LED chip, its combination with blue and green LED chips to achieve color light output increases the overall power consumption of the device.

[0052] Table 2

[0053] Temperature / °C Percentage of luminous efficiency drop % 40 25 50 40

[0054] In display panels that include red, green, and blue LED chips, achieving high pixel density (ppi) is difficult due to limitations imposed by the placement of the LED pads, the size of the LED chips, and the precision of the die-bonding technology. For example, in the aforementioned display panels, multiple LED chips are arranged in an array. Along the arrangement direction of these chips, the minimum pitch (e.g., the distance between the geometric centers of adjacent LED chips) is approximately several hundred micrometers, significantly limiting the development of high pixel density display panels.

[0055] Embodiments of this disclosure provide a display substrate and a display device. The display substrate includes a plurality of light-emitting diode (LED) chips, each LED chip including a plurality of light-emitting units that emit light of different colors. Each light-emitting unit includes a first electrode, a light-emitting layer, a substrate, and a second electrode, with the substrate and the second electrode located on opposite sides of the light-emitting layer. In each LED chip, the plurality of light-emitting units share a substrate and a first electrode, the light-emitting layers of the plurality of light-emitting units emit light of the same color, and at least one light-emitting unit further includes a first color conversion layer located on the side of the substrate away from the light-emitting layer to convert the first color light emitted by the light-emitting layer into a second color light. In the display substrate provided by this disclosure, on the one hand, by dividing each LED chip into segments so that the same LED chip emits at least two different colors of light, the high pixel density requirement of the display panel can be achieved; on the other hand, by having the plurality of light-emitting units in each LED chip share a first electrode, the effective light-emitting area of ​​each light-emitting unit can be maximized.

[0056] The display substrate and display device provided in the embodiments of this disclosure are described below with reference to the accompanying drawings.

[0057] Figure 3 This is a plan view of a display substrate provided according to an embodiment of the present disclosure. Figure 4 For along Figure 3 The diagram shows a partial cross-sectional structure of the substrate cut by line AA'. Figure 3 and Figure 4 As shown, the display substrate includes a plurality of light-emitting diode chips 1000. For example, the plurality of light-emitting diode chips 1000 can be arranged in an array along a first direction (e.g., the X direction) and a second direction (e.g., the Y direction). Figure 3 The diagram illustrates that the first and second directions are perpendicular, but it is not limited to this. The first and second directions may not be perpendicular; they only need to intersect. For example, the first and second directions can be interchanged.

[0058] like Figure 3 and Figure 4As shown, each light-emitting diode chip 1000 includes multiple light-emitting units 10 that emit light of different colors, for example, at least two light-emitting units 10. Each light-emitting unit 10 includes a second electrode 12, a light-emitting layer 13, and a substrate 14 stacked sequentially, i.e., the second electrode 12 and the substrate 14 are located on opposite sides of the light-emitting layer 13. Each light-emitting unit 10 also includes a first electrode 15, for example, each light-emitting unit 10 also includes a first contact pad 16 connected to the first electrode 15. In each light-emitting diode chip 1000, multiple light-emitting units 10 share the substrate 14 and the first electrode 15, the light-emitting layer 13 of multiple light-emitting units 10 emits light of the same color, and at least one light-emitting unit 10 also includes a first color conversion layer 210 located on the side of the substrate 14 away from the light-emitting layer 13, to convert the first color light emitted by the light-emitting layer 13 into a second color light. In the display substrate provided in this disclosure, on the one hand, by dividing each light-emitting diode chip into segments so that the same light-emitting diode chip emits at least two different colors of light, the high pixel density requirement of the display panel can be achieved; on the other hand, the multiple light-emitting units included in each light-emitting diode chip share a first electrode, which can maximize the effective light-emitting area of ​​each light-emitting unit.

[0059] For example, in each LED chip 1000, multiple light-emitting units 10 share a first contact pad 16.

[0060] For example, such as Figure 4 As shown, each light-emitting diode chip 1000 includes a first electrode 15 and multiple second electrodes 12, each light-emitting unit 10 includes a second electrode 12, and multiple light-emitting units 10 share a first electrode 15. The orthogonal projection of the first contact pad 16 onto the substrate 14 should avoid overlapping with the orthogonal projection of the light-emitting layer 13 of each light-emitting unit 10 onto the substrate 14. By providing the aforementioned first contact pad 16, the effective area of ​​the first electrode 15 when electrically connected to other electrical structures (e.g., terminals, pads, etc.) can be expanded, while ensuring that the effective light-emitting area of ​​each light-emitting unit is not lost.

[0061] For example, such as Figure 4 As shown, each light-emitting unit 10 further includes a first conductivity type semiconductor layer 18 located between the light-emitting layer 13 and the substrate 14 and a second conductivity type semiconductor layer 17 located between the light-emitting layer 13 and the second electrode 12. The first conductivity type semiconductor layer 18 is connected to the first electrode 15, and the second conductivity type semiconductor layer 17 is connected to the second electrode 12.

[0062] For example, such as Figure 4 As shown, the substrate 14 includes a sapphire layer 140 and a buffer layer 14-1 located between the sapphire layer 140 and the first conductivity type semiconductor layer 18, so that the first conductivity type semiconductor layer can be more easily formed on the substrate.

[0063] For example, such as Figure 4 As shown, each light-emitting diode chip also includes a barrier layer 19 for separating the light-emitting layer 13, the second electrode 12, and the second conductivity type semiconductor layer 17 of adjacent light-emitting units 10. That is, the light-emitting layer 13 of adjacent light-emitting units 10 is separated from each other by the barrier layer 19, the second electrode 12 of adjacent light-emitting units 10 is insulated from each other by the barrier layer 19, and the second conductivity type semiconductor layer 17 in adjacent light-emitting units 10 is separated from each other by the barrier layer 19.

[0064] For example, in each light-emitting diode chip, the multiple light-emitting layers 13 of the multiple light-emitting units 10 can be made of the same material so that the light-emitting layers 13 of the multiple light-emitting units 10 emit light of the same color.

[0065] For example, in each light-emitting diode chip, the multiple second electrodes 12 of the multiple light-emitting units 10 can be made of the same material, but are not limited to this, and can also be made of different materials; the multiple second conductivity type semiconductor layers 17 of the multiple light-emitting units 10 can be made of the same material, but are not limited to this, and can also be made of different materials.

[0066] For example, such as Figure 4 As shown, in each light-emitting diode chip, the first conductivity type semiconductor layer 18 is a whole semiconductor layer shared by multiple light-emitting units 10, and the first electrode 15 serves as the common electrode of multiple light-emitting units 10 by being connected to the shared first conductivity type semiconductor layer 18.

[0067] It should be noted that the "conductivity type" mentioned above includes n-type or p-type. For example, the first conductivity type semiconductor layer can be an n-type semiconductor layer, and the second conductivity type semiconductor layer can be a p-type semiconductor layer. Of course, the embodiments of this disclosure include, but are not limited to, the first conductivity type semiconductor layer can be a p-type semiconductor layer, and the second conductivity type semiconductor layer can be an n-type semiconductor layer.

[0068] For example, when the first color light emitted by the light-emitting layer of multiple light-emitting units is blue light, the first conductivity type semiconductor layer is a p-type semiconductor layer and the second conductivity type semiconductor layer is an n-type semiconductor layer.

[0069] For example, the first conductivity type semiconductor layer 18 is a p-type semiconductor layer, and the second conductivity type semiconductor layer 17 is an n-type semiconductor layer. Holes and electrons are injected into the second conductivity type semiconductor layer 17 and the first conductivity type semiconductor layer 18 from the second electrode 12 and the first electrode 15, respectively, and recombine in the light-emitting layer 13, thus releasing energy in the form of photons. The emission wavelength depends on the band gap of the light-emitting material.

[0070] For example, in some examples, the first conductivity type semiconductor layer 18 is an n-type gallium nitride layer, and the second conductivity type semiconductor layer 17 is a p-type gallium nitride layer. Of course, embodiments of this disclosure include, but are not limited to, the first conductivity type semiconductor layer can be a p-type gallium nitride layer, and the second conductivity type semiconductor layer can be an n-type gallium nitride layer.

[0071] For example, when the light-emitting layer of each light-emitting unit is used to emit light in the blue-green band, the intrinsic semiconductor material of the first conductivity type semiconductor layer and the second conductivity type semiconductor layer can be gallium nitride (GaN). Of course, the embodiments of this disclosure include, but are not limited to, the first conductivity type semiconductor layer and the second conductivity type semiconductor layer described above can also be made of other suitable materials.

[0072] For example, in some examples, the material of the light-emitting layer 13 includes multiple quantum wells (MQWs), which are systems of multiple quantum wells combined together, and can improve the luminous intensity and luminous efficiency of the light-emitting unit. Of course, the embodiments of this disclosure include, but are not limited to, the light-emitting layer described above can also be other suitable light-emitting structures such as quantum wells or PN junctions.

[0073] For example, such as Figure 4 As shown, each light-emitting unit 10 also includes a plurality of second contact pads 11 disposed in the same layer as the first contact pad 16, and each second contact pad 11 is connected to the corresponding second electrode 12.

[0074] Since the second contact pad 11 is connected to the second electrode, its orthographic projection on the substrate 14 partially overlaps with the orthographic projection of the light-emitting layer 13 of each light-emitting unit 10 on the substrate 14. By providing the second contact pad 11, the effective area of ​​the second electrode 15 when electrically connected to other electrical structures (such as terminals, pads, etc.) can be expanded.

[0075] For example, the distance between the first contact pad 16 and the second contact pad 11 is not less than a safety distance to ensure that there is no interference between them; for example, the safety distance can be 30 micrometers. The aforementioned safety distance refers to the shortest distance between the two contact pads that can avoid short circuits (i.e., the shortest distance between the edges of the two contact pads that are close to each other). The embodiments of this disclosure are not limited thereto, and the safety distance can be reduced according to the advancement of process technology.

[0076] For example, the materials of the first electrode 15 and the second electrode 12 in each light-emitting unit 10 need to have good ohmic contact characteristics, so as to achieve good ohmic contact with the first conductivity type semiconductor 18 and the second conductivity type semiconductor layer 17, which is beneficial to the transmission of current. Specifically, the materials of the first electrode 15 and the second electrode 12 can be selected from at least one metal or alloy including aluminum, chromium, platinum, gold, and silver. The materials of the first contact pad 16 and the second contact pad 11 need to take into account the robustness of electrical connection with other electrical structures (such as terminals, pads, etc.), and their materials can be selected from at least one metal or alloy including tin, silver, copper, nickel, and gold.

[0077] For example, such as Figure 4 As shown, each light-emitting diode chip includes a first color light-emitting unit 100, a second color light-emitting unit 200, and a third color light-emitting unit 300. The first color light-emitting unit 100 is configured to emit a first color light. The second color light-emitting unit 200 also includes a first color conversion layer 210 located on the side of the substrate 14 away from the light-emitting layer 13 and emits a second color light. The third color light-emitting unit 300 also includes a second color conversion layer 310 located on the side of the substrate 14 away from the light-emitting layer 13 to convert the first color light emitted by the light-emitting layer 13 into a third color light.

[0078] For example, such as Figure 4 As shown, a color conversion layer is disposed on one side of the substrate 14, and a first conductive semiconductor layer 18, a light-emitting layer 13, a second conductive semiconductor layer 17, a second electrode 12, a first electrode 15, a first contact pad 16, and a second contact pad 11 are disposed on the other side.

[0079] For example, such as Figure 4 The illustration shows a light-emitting diode (LED) chip including a first color light-emitting unit, a second color light-emitting unit, and a third color light-emitting unit, but is not limited thereto. The LED chip may include at least one first color light-emitting unit, at least one second color light-emitting unit, and at least one third color light-emitting unit.

[0080] For example, the first color light-emitting unit 100 is a blue light-emitting unit, and one of the second color light-emitting unit 200 and the third color light-emitting unit 300 is a red light-emitting unit, while the other is a green light-emitting unit. For example, if the second color light-emitting unit is a green light-emitting unit and the third color light-emitting unit is a red light-emitting unit, then the first color light is blue light, the second color light is green light, and the third color light is red light.

[0081] For example, blue light can excite the first color conversion layer 210 to emit green light and excite the second color conversion layer 310 to emit red light.

[0082] For example, the materials of the first color conversion layer 210 and the second color conversion layer 310 include quantum dot materials or fluorescent materials. For example, quantum dots (QDs), also known as nanocrystals, generally have a particle size between 1 and 20 nanometers. Because electrons and holes are quantum confined, the continuous band structure becomes a discrete energy level structure with molecular characteristics. When excited, they can emit light of a different color than the excitation light.

[0083] For example, such as Figure 4 As shown, a pixel defining portion 150 is provided on the side of the substrate 14 away from the light-emitting layer 13. The pixel defining portion 150 includes a plurality of openings 151 to define a plurality of light-emitting regions of a plurality of light-emitting units 20, such as the first light-emitting region 101 of the first color light-emitting unit 100, the second light-emitting region 201 of the second color light-emitting unit 200, and the third light-emitting region 301 of the third color light-emitting unit 300. A first color conversion layer 210 is provided in the opening 151 of the second color light-emitting unit 200, and a second color conversion layer 310 is provided in the opening 151 of the third color light-emitting unit 300. For example, scattering particles 110 can be provided in the opening 151 of the first color light-emitting unit 100, and a transparent material including scattering particles 110 can be provided in the opening 151 of the first color light-emitting unit 100, such as photoresist, acrylic system, or silicone system. The aforementioned scattering particles 110 may include materials such as titanium dioxide (TiO2), silicon dioxide (SiO2), barium sulfate (BaSO4), and zirconium dioxide (ZrO2), and the size of the scattering particles 110 may be 200–300 nanometers. The aforementioned light-emitting region refers to the area defined by the opening of the pixel defining portion on the side of the substrate away from the light-emitting layer. When the cross-section of the pixel defining portion is trapezoidal, the opening formed by the edge of the pixel defining portion away from the substrate is the light-emitting region. This light-emitting region is the area where light is emitted from the color conversion layer or the film layer containing the scattering particles.

[0084] For example, such as Figure 4 As shown, the pixel defining portion 150 between adjacent openings 151 is perpendicular to Figure 3 The cross-section of the XY plane shown can be trapezoidal or rectangular, and this embodiment of the present disclosure is not limited to either. The aforementioned XY plane can be a plane in which multiple light-emitting diode chip arrays are arranged.

[0085] For example, such as Figure 4 As shown, a color filter layer 30 is provided on the side of the color conversion layer away from the substrate 14. For example, a first color filter layer is provided on the side of the opening 151 of the first color light-emitting unit 100, a second color filter layer is provided on the side of the opening 151 of the second color light-emitting unit 200, and a third color filter layer is provided on the side of the opening 151 of the third color light-emitting unit 300. For example, a black matrix 40 can also be provided between adjacent color filter layers 30.

[0086] Figure 5 It is a partial cross-sectional structure schematic diagram of the second-color light-emitting unit and the third-color light-emitting unit. As Figure 5 shown, the material of the buffer layer 14-1 can be gallium nitride.

[0087] Due to the relatively large thickness of the sapphire layer (for example, greater than 60 microns), color crosstalk is likely to occur between adjacent light-emitting units. For example, the light emitted by the light-emitting layer of the second-color light-emitting unit is likely to enter the color conversion layer of the third-color light-emitting unit, or the light emitted by the light-emitting layer of the third-color light-emitting unit is likely to enter the color conversion layer of the second-color light-emitting unit, etc. Therefore, when dividing each light-emitting diode chip, the distance between the light-emitting regions of adjacent light-emitting units needs to be considered. It is necessary to minimize the color crosstalk ratio between adjacent light-emitting units as much as possible and also minimize the size of the light-emitting diode chip.

[0088] For example, the refractive index of the light-emitting layer 13 is 2.54, the refractive indices of the first-conductive-type semiconductor layer 18 and the buffer layer 14-1 are both 2.45, the refractive index of the sapphire layer 140 is 1.77, and the refractive indices of the first color conversion layer 210 and the second color conversion layer 310 are 1.5. When the first-color light emitted by the light-emitting layer 13 passes through each film layer located between the color conversion layer and the light-emitting layer 13, total reflection will occur when the incident angle of the incident light satisfies the total reflection critical angle. When the incident angle of the light emitted by the light-emitting layer at the interface of each film layer is at least the total reflection critical angle, the color crosstalk ratio of the light emitted by adjacent light-emitting units during the process of passing through the first-conductive-type semiconductor layer, the buffer layer, and the sapphire layer can be minimized as much as possible.

[0089] For example, as Figure 5 shown, the incident angle of the light ray 131 emitted from the edge of the light-emitting layer 13 of each color light-emitting unit when total reflection occurs at the interface between the buffer layer 14-1 and the sapphire layer 140 is the total reflection critical angle θ1, and the incident angle of the light ray 131 emitted from the edge of the light-emitting layer 13 of each color light-emitting unit when total reflection occurs at the interface between the sapphire layer 140 and the color conversion layer is the total reflection critical angle θ2. According to the refractive index n of each above-mentioned film layer and the total reflection critical angle θ c satisfying the formula sinθ c = n2 / n1, n2 < n1, the total reflection critical angle θ1 is calculated to be approximately 46°, and the total reflection critical angle θ2 is calculated to be approximately 58°.

[0090] For example, as Figure 5As shown, the thickness of the light-emitting layer 13 can be 0.3 micrometers, the thickness of the first conductivity type semiconductor layer 18 and the buffer layer 14-1 can both be 2 micrometers, and the thickness of the color conversion layer can be 10 micrometers. However, according to current process conditions, the thickness of the sapphire layer 140 can be reduced to a maximum of 60 micrometers. Based on the total internal reflection critical angle θ1, the total thickness H of the first conductivity type semiconductor layer 18 and the buffer layer 14-1, and the relationship d1 = H * tanθ1, d1 can be calculated to be approximately 4.2 micrometers. Based on the thickness h of the sapphire layer 140, the total internal reflection critical angle θ2, and the relationship d2 = h * tanθ2, d2 can be calculated to be approximately 95.8 micrometers. Therefore, the distance (d1 + d2) between the light-emitting areas of adjacent light-emitting units is approximately 100 micrometers. Thus, a distance of at least 100 micrometers between adjacent light-emitting units is necessary to significantly reduce the cross-color ratio between adjacent light-emitting units.

[0091] Of course, when the thickness of at least one of the above-mentioned film layers changes, or when the material of at least one of the above-mentioned film layers changes and causes a change in refractive index, the distance between the light-emitting areas of the adjacent light-emitting units will also change.

[0092] For example, Table 3 shows the numerical relationships simulated after setting the distance between adjacent light-emitting units to be no less than 100 micrometers. As shown in Table 3, the brightness of the red light emitted by the red light-emitting unit, the green light emitted by the green light-emitting unit, and the blue light emitted by the blue light-emitting unit in the display panel were collected using a full-area receiver. The illuminance of the red light was found to be 7.05*10. 10 Lux, green light intensity is 6.91*10 10 Lux, blue light intensity is 6.05*10 10 Lux.

[0093] Table 3

[0094]

[0095] When a local receiver is used to collect the light intensity of the area where the red light-emitting unit is located, the illuminance of the red light is 2.02*10. 10 Lux received a green light intensity of 5.14*10. 7 Lux received a blue light intensity of 7.67*10. 7 Lux, thus, the cross-color ratio of green light-emitting units to red light-emitting units is approximately 0.07%, and the cross-color ratio of blue light-emitting units to red light-emitting units is approximately 0.11%.

[0096] When a local receiver is used to collect light intensity data for the area where the green emitting unit is located, the illuminance of the green emitting unit is 1.78*10. 10Lux received 4.27*10 ppm of light from the red emitting unit. 7 Lux received a light intensity of 3.20*10 from the blue emitting unit. 8 Lux, thus, the cross-color ratio of the green light-emitting unit to the red light-emitting unit is approximately 0.06%, and the cross-color ratio of the blue light-emitting unit to the red light-emitting unit is approximately 0.46%.

[0097] When a local receiver is used to collect the light intensity of the area where the blue emitting unit is located, the illuminance of the blue emitting unit is 4.93*10. 9 Lux received 1.73*10 lux of light from the red emitting unit. 7 Lux receives 1.00*10 lux of light from the green light-emitting unit. 8 Lux, thus, the cross-color ratio of the red light-emitting unit to the blue light-emitting unit is approximately 0.03%, and the cross-color ratio of the green light-emitting unit to the blue light-emitting unit is approximately 0.17%.

[0098] As can be seen from the simulation results shown in Table 3, the proportion of each color crossing is less than 1%.

[0099] For example, if the first color conversion layer is configured to convert incident blue light into green light, and the second color conversion layer is configured to convert incident blue light into red light, and the blue light emitted by the light-emitting layer in the first color light-emitting unit is emitted directly without conversion, then the blue light conversion efficiency of the first color light-emitting unit can be considered as 1, the conversion efficiency of the first color conversion layer in the second color light-emitting unit to convert blue light into green light can be 0.483, and the conversion efficiency of the second color conversion layer in the third color light-emitting unit to convert blue light into red light can be 1.112.

[0100] For example, Table 4 shows the color coordinates of red light emitted by the red light-emitting unit, green light emitted by the green light-emitting unit, and blue light emitted by the blue light-emitting unit, as well as the coordinates of the white point used to achieve white balance after mixing.

[0101] Table 4

[0102] x y z Red light emitted by the red light emitting unit 0.695 0.302 0.003 Green light emitted by the green light emitting unit 0.137 0.79 0.073 Blue light emitted by the blue light emitting unit 0.1446 0.0362 0.8192 White light formed by mixing 0.28 0.29 0.43

[0103] For example, as shown in Table 4, the color coordinates (x, y, z) of the red light emitted by the red light-emitting unit are (0.695, 0.302, 0.003), the color coordinates (x, y, z) of the green light emitted by the green light-emitting unit are (0.137, 0.79, 0.073), the color coordinates (x, y, z) of the blue light emitted by the blue light-emitting unit are (0.1446, 0.0362, 0.8192), and the white point coordinates (x, y, z) of the white light formed by the mixture are (0.28, 0.29, 0.43).

[0104] Based on the color coordinate data above, the white balance ratio for red, green, and blue light is calculated to be 0.2598:0.6776:0.0626. Of course, the white balance ratio will differ depending on the color coordinate data of the different colors of light.

[0105] For example, by setting the blue light emitted by the light-emitting layers of different color light-emitting units in a light-emitting diode chip to the same brightness, the quantum dot material in the color conversion layer can be irradiated with light of the same brightness, thereby ensuring that different color conversion layers have the same lifespan as much as possible.

[0106] In some embodiments, the area of ​​the light-emitting region of different color light-emitting units is different.

[0107] For example, for a 55-inch display panel with a 4K resolution, the pixel pitch can be set to 318 micrometers. Based on the size of the LED chip and the display panel's required brightness of 1000 nits, the aperture ratio of the different colored light-emitting units in the LED chip is designed. Based on the conversion efficiency of the different color conversion layers and the white balance ratio of different colors of light, the area ratio of the emitting areas of the red, green, and blue light-emitting units is calculated to be 1.285:0.989:0.320. Therefore, the aperture ratios of the red, green, and blue light-emitting units are 1.285%, 0.989%, and 0.320%, respectively. The aperture ratio refers to the ratio of the emitting area area to the pixel area. Each pixel area includes three different colored light-emitting units, and different colored light-emitting units can have different emitting area areas.

[0108] Therefore, the area of ​​the luminous region of the red luminous unit is larger than that of the green luminous unit, and the area of ​​the luminous region of the green luminous unit is larger than that of the blue luminous unit.

[0109] For example, based on the area relationship of the emitting areas of the different colored emitting units, the emitting area of ​​the red emitting unit can be set as a rectangle with dimensions of 25μm*52μm, or a circle with a radius of 20.34μm; the emitting area of ​​the green emitting unit can be set as a rectangle with dimensions of 40μm*25μm, or a circle with a radius of 17.84μm; and the emitting area of ​​the blue emitting unit can be set as a square with dimensions of 18μm*18μm, or a circle with a radius of 10.15μm. The above-mentioned emitting area dimensions for each color emitting unit are merely examples, and each dimension can vary within a range of ±10%.

[0110] For example, Figure 6 and Figure 7 This is a schematic diagram of the planar distribution of multiple light-emitting units in a light-emitting diode chip according to an example of an embodiment of the present disclosure.Figure 3 The AA' line shown is along Figure 6 The cut-off line is shown in the distribution structure of multiple light-emitting units. For example... Figure 6 and Figure 7 As shown, in each LED chip, the line connecting the geometric centers of the light-emitting areas 101 of the first color light-emitting unit, 201 of the second color light-emitting unit, and 301 of the third color light-emitting unit forms a first triangle 1001. The ratio of the shortest distances between the edges of the light-emitting areas of different color light-emitting units is 0.6 to 1.5. For example, the ratio of the shortest distances between the edges of the light-emitting areas of different color light-emitting units is 0.8 to 1.2. For example, the ratio of the shortest distances between the edges of the light-emitting areas of different color light-emitting units is 0.9 to 1.1.

[0111] The aforementioned "geometric center" refers to the geometric center of the shape of the luminescent area.

[0112] The aforementioned "shortest distance between the edges of the light-emitting areas of different color light-emitting units" refers, for example, the shortest distance E3 between the edges of the light-emitting area 101 of the first color light-emitting unit and the light-emitting area 201 of the second color light-emitting unit that are close to each other, the shortest distance E2 between the edges of the light-emitting area 201 of the second color light-emitting unit and the light-emitting area 301 of the third color light-emitting unit that are close to each other, and the shortest distance E1 between the edges of the light-emitting area 101 of the first color light-emitting unit and the light-emitting area 301 of the third color light-emitting unit that are close to each other.

[0113] For example, E1 is not less than 100 micrometers, for example, 100 micrometers; E2 is not less than 100 micrometers, for example, 102 micrometers; E3 is not less than 100 micrometers, for example, 100 micrometers.

[0114] For example, such as Figure 6 and Figure 7 As shown, the light-emitting areas of multiple light-emitting units in each LED chip are distributed within a rectangular area 2001. The light-emitting area 101 of the first color light-emitting unit, the light-emitting area 102 of the second color light-emitting unit, and the light-emitting area 103 of the third color light-emitting unit are located at the three right angles of the rectangular area 2001, respectively.

[0115] For example, such as Figure 6 As shown, when each light-emitting area is rectangular, two adjacent sides of each light-emitting area can coincide with two adjacent sides of the rectangular region 2001, and one right angle of each light-emitting area can coincide with one right angle of the rectangular region 2001. The three right angles of the three light-emitting areas coincide with the three right angles of the rectangular region 2001, respectively. Thus, the intersection of the edges of multiple light-emitting areas can define a rectangular region 2001. This embodiment is not limited to this; when each light-emitting area is circular, the sides of the rectangular region can be tangents to the circle.

[0116] like Figure 6 As shown, in some embodiments, the rectangular region 2001 is located within the outer contour 2002 of the pixel defining portion 150, and the distance C between the outer contour 2002 of the pixel defining portion 150 and the rectangular region 2001 can be 15-20 micrometers. The pixel defining portion 150 can be made of a light-absorbing material, such as a dark resin material. The thickness of the pixel defining portion is substantially the same as the thickness of the color conversion layer, for example, it can be 10-15 micrometers. In some embodiments, a cutting line 2003 is provided around the pixel defining portion. It is understood that a light-emitting diode chip motherboard can include multiple light-emitting diode chips. Multiple light-emitting diode chips can be obtained by cutting the light-emitting diode chip motherboard along the cutting line 2003 using a laser. Therefore, the cutting line 2003 is the contour line of each light-emitting diode chip. For example, the distance B between the cutting line 2003 and the outer boundary 2002 of the pixel defining portion is 10-20 micrometers. When designing pixels on the display substrate, the area enclosed by each pixel region 2004 should be slightly larger than the contour line of each light-emitting diode chip, i.e., the cutting line 2003. Multiple pixel regions 2004 of the display substrate are arranged in an adjacent array, meaning that the boundaries of adjacent pixel regions 2004 can overlap. There can be a distance A between the pixel region 2004 and the cutting line 2003. The distance A can prevent interference between the light-emitting diode chips, and can be 27.5 to 47.5 micrometers.

[0117] For example, such as Figure 6 As shown, the boundary of the LED chip, i.e., the dicing line 2003, is, for example, rectangular, and one side length D1 of the LED chip can be 243 micrometers. For example, the pitch of the LED chip can be 318 micrometers. For example, the pitch of the LED chip refers to the distance between the geometric centers of the light-emitting areas of adjacent LED chips along the arrangement direction of the LED chips (e.g., at least one of a first direction and a second direction). For example, the pitch of the LED chip and... Figure 6 The side length D2 of the pixel region 2004 shown can be equal.

[0118] In this disclosure, by arranging multiple light-emitting units in a triangular configuration in a light-emitting diode chip, the cross-color ratio of different color light-emitting units can be greatly reduced while the pitch of the light-emitting diode chip can be set to be smaller.

[0119] For example, such as Figure 6 and Figure 7As shown, in each LED chip, the second contact pad 11-1 of the first color light-emitting unit, the second contact pad 11-2 of the second color light-emitting unit, and the second contact pad 11-3 of the third color light-emitting unit can be respectively distributed at the three right-angle positions of the rectangular area 2001, and the first contact pad 15 is located at the fourth right-angle position of the rectangular area 2001. For example, each LED chip includes three second contact pads 11 and one first contact pad 15, with the four contact pads respectively distributed at the four right-angle positions of the rectangle.

[0120] For example, such as Figure 6 and Figure 7 As shown, when each contact pad is rectangular, two adjacent sides of each contact pad can coincide with two adjacent sides of the rectangular region 2001, and one right angle of each contact pad can coincide with one right angle of the rectangular region 2001. The four right angles of the four contact pads coincide with the four right angles of the rectangular region 2001, thus the edges of the four contact pads can define a rectangular region 2001. This embodiment is not limited to this; when each contact pad is circular, the edges of the rectangular region can be tangents to the circle. Figure 6 and Figure 7 The diagram schematically shows the overlap between the light-emitting area of ​​each light-emitting unit and the second contact pad, but it is not limited to this; the light-emitting area of ​​each light-emitting unit and the second contact pad may not overlap.

[0121] For example, the size of each contact pad can be 30μm*30μm, but it is not limited to this and can be adjusted by ±5% within this size.

[0122] In this disclosure, each LED chip, by placing four contact pads of the same layer at the four corners of a rectangle, ensures that the minimum distance between the edges of any two contact pads is greater than a safety distance, thus preventing interference between them. For example, the safety distance can be 30 micrometers. The embodiments of this disclosure are not limited to this; the safety distance can be reduced according to advancements in process technology.

[0123] In this disclosure, multiple light-emitting units emitting different colors of light are arranged within the same light-emitting diode chip. The positions of the light-emitting areas and contact pads of these units are precisely configured, which significantly reduces crosstalk between adjacent light-emitting units and increases the pixel density of the display substrate. Furthermore, by controlling the light-emitting layers of different light-emitting units in each light-emitting diode chip to emit the same intensity of the first color light, the lifespan of the materials in different color conversion layers can be ensured to be approximately the same. White balance is then achieved by adjusting the area (aperture ratio) of the light-emitting areas of the different color light-emitting units. For example, this disclosure provides a miniature light-emitting diode display substrate with anti-crosstalk and high-resolution characteristics.

[0124] For example,Figure 8 and Figure 9 This is a schematic diagram showing the planar distribution of multiple light-emitting units in a light-emitting diode chip according to another example of an embodiment of this disclosure. Figure 8 and Figure 9 As shown, in each LED chip, the line connecting the geometric centers of the light-emitting area 101 of the first color light-emitting unit, the light-emitting area 201 of the second color light-emitting unit, and the light-emitting area 301 of the third color light-emitting unit forms a first triangle, which is an acute triangle.

[0125] For example, the shortest distance E1 between the adjacent edges of the light-emitting area 101 of the first color light-emitting unit and the light-emitting area 301 of the third color light-emitting unit is not less than 100 micrometers, for example, 104 micrometers or 100 micrometers; the shortest distance E2 between the adjacent edges of the light-emitting area 201 of the second color light-emitting unit and the light-emitting area 301 of the third color light-emitting unit is not less than 100 micrometers, for example, 100 micrometers; the shortest distance E3 between the adjacent edges of the light-emitting area 101 of the first color light-emitting unit and the light-emitting area 201 of the second color light-emitting unit is not less than 100 micrometers, for example, 129 micrometers or 100 micrometers.

[0126] For example, such as Figure 8 and Figure 9 As shown, the light-emitting areas of multiple light-emitting units in each LED chip are distributed within a rectangular area 2001. Two of the light-emitting areas 101 of the first color light-emitting unit, 102 of the second color light-emitting unit, and 103 of the third color light-emitting unit are located at two adjacent right angles in the rectangular area 2001, and the other is located at the side of the rectangular area 2001 opposite to the two adjacent right angles.

[0127] For example, such as Figure 8 As shown, when the shape of each light-emitting area is rectangular, the two adjacent sides of each light-emitting area located at two right angles coincide with the two adjacent sides of the rectangular region 2001, and one right angle of each light-emitting area can coincide with one right angle of the rectangular region 2001. One side of the light-emitting area located on the edge coincides with the edge of the rectangular region 2001. Thus, a rectangular region 2001 can be defined by the edges of the light-emitting areas of different light-emitting units.

[0128] For example, such as Figure 8As shown, the rectangular region 2001 is located within the outer contour 2002 of the pixel defining portion 150. The distance C between the outer contour 2002 of the pixel defining portion 150 and the rectangular region 2001 can be 15 to 25 micrometers, for example, 20 micrometers. For example, the distance B between the cutting line 2003 provided on the periphery of the pixel defining portion 150 and the outer boundary 2002 of the pixel defining portion is 10 to 20 micrometers, for example, 15 micrometers. For example, the distance A between the pixel region 2004 and the cutting line 2003 can be 27.5 to 47.5 micrometers, for example, 37.5 micrometers.

[0129] For example, such as Figure 8 As shown, the boundary of the LED chip, i.e., the dicing line 2003, is, for example, a square, and the side length D1 of the LED chip can be 215 micrometers. For example, the pitch of the LED chip can be 252.5 micrometers. For example, the pitch of the LED chip is... Figure 8 The side length D2 of the pixel region 2004 shown can be equal.

[0130] For example, such as Figure 8 and Figure 9 As shown, in each LED chip, the geometric center line connecting the second contact pad 11-1 of the first color light-emitting unit, the second contact pad 11-2 of the second color light-emitting unit, and the second contact pad 11-3 of the third color light-emitting unit forms a second triangle 1002, and at least a portion of the first contact pad 15 is located within the second triangle 1002.

[0131] For example, the geometric center of the first contact pad 15 is located within the second triangle 1002. For example, the entire first contact pad 15 is located within the second triangle 1002.

[0132] For example, the distance E4 between the adjacent edges of the second contact pad 11-3 and the first contact pad 15 of the third color light-emitting unit can be 32.5 micrometers. For example, the distance between the adjacent edges of the second contact pad and the first contact pad 15 of other color light-emitting units is greater than the safety distance, for example, 30 micrometers.

[0133] For example, such as Figure 8 and Figure 9 As shown, in the plane perpendicular to the first and second directions, the light-emitting area of ​​each light-emitting unit may or may not overlap with the second contact pad.

[0134] In this disclosure, each light-emitting diode chip can ensure that the distance between any two contact pads is greater than the safety distance by placing at least a portion of the first contact pads disposed on the same layer in a triangle formed by the geometric centers of the three second contact pads, so as to ensure that there is no interference between them. For example, the safety distance can be 30 micrometers. The embodiments of this disclosure are not limited to this, and the safety distance can be reduced according to the advancement of process technology.

[0135] For example, Figure 10 This is a schematic diagram showing the planar distribution of multiple light-emitting units in a light-emitting diode chip according to another example of an embodiment of this disclosure. Figure 10 As shown, in each LED chip, the line connecting the geometric centers of the light-emitting area 101 of the first color light-emitting unit, the light-emitting area 201 of the second color light-emitting unit, and the light-emitting area 301 of the third color light-emitting unit forms a first triangle, which is an acute triangle.

[0136] For example, the shortest distance E1 between the adjacent edges of the light-emitting area 101 of the first color light-emitting unit and the light-emitting area 301 of the third color light-emitting unit is not less than 100 micrometers, for example, 134 micrometers or 100 micrometers; the shortest distance E2 between the adjacent edges of the light-emitting area 201 of the second color light-emitting unit and the light-emitting area 301 of the third color light-emitting unit is not less than 100 micrometers, for example, 100 micrometers; the shortest distance E3 between the adjacent edges of the light-emitting area 101 of the first color light-emitting unit and the light-emitting area 201 of the second color light-emitting unit is not less than 100 micrometers, for example, 140 micrometers or 100 micrometers.

[0137] For example, such as Figure 10 As shown, the light-emitting areas of multiple light-emitting units in each LED chip are distributed within a rectangular area 2001. Two of the light-emitting areas 101 of the first color light-emitting unit, 102 of the second color light-emitting unit, and 103 of the third color light-emitting unit are located at two adjacent right angles in the rectangular area 2001, and the other is located at the side of the rectangular area 2001 opposite to the two adjacent right angles.

[0138] For example, such as Figure 10 As shown, when each light-emitting area is circular, the side of the rectangular area can be a tangent to the circle. For example, at least one light-emitting area can also be elliptical or teardrop-shaped.

[0139] For example, such as Figure 10As shown, the line width C of the pixel defining portion can be 15 to 25 micrometers, for example, 20 micrometers. For example, the distance B between the cutting line 2003 and the outer boundary 2002 of the pixel defining portion can be 10 to 20 micrometers, for example, 15 micrometers. For example, the distance A between the pixel region 2004 and the cutting line 2003 can be 27.5 to 47.5 micrometers, for example, 37.5 micrometers.

[0140] For example, such as Figure 10 As shown, the boundary of the LED chip, i.e., the dicing line 2003, is, for example, a square, and the side length D1 of the LED chip can be 226 micrometers. For example, the pitch of the LED chip can be 263.5 micrometers. For example, the pitch of the LED chip is... Figure 10 The side length D2 of the pixel region 2004 shown can be equal.

[0141] For example, such as Figure 10 As shown, in each LED chip, the geometric center line connecting the second contact pad 11-1 of the first color light-emitting unit, the second contact pad 11-2 of the second color light-emitting unit, and the second contact pad 11-3 of the third color light-emitting unit forms a second triangle, and at least a portion of the first contact pad 15 is located within the second triangle.

[0142] For example, the geometric center of the first contact pad 15 is located within the second triangle 1002. For example, the entire first contact pad 15 is located within the second triangle.

[0143] For example, the distance E4 between the adjacent edges of the second contact pad 11-1 and the first contact pad 15 of the first color light-emitting unit can be 38.5 micrometers. For example, the distance between the adjacent edges of the second contact pad and the first contact pad 15 of other color light-emitting units is greater than the safety distance, such as 30 micrometers.

[0144] For example, such as Figure 10 As shown, in the plane perpendicular to the first and second directions, the light-emitting area of ​​each light-emitting unit may or may not overlap with the second contact pad.

[0145] The embodiments disclosed herein do not limit the shape of the light-emitting area of ​​each light-emitting unit. For example, it can be a regular shape such as a triangle, hexagon, or teardrop, or it can be an irregular shape. For example, in each light-emitting diode chip, the shapes of the light-emitting areas of multiple light-emitting units can be the same or different.

[0146] For example, Figures 11 to 16 This is a partial process flow diagram for forming a light-emitting diode (LED) chip. (Example:) Figure 11As shown, a first conductivity type semiconductor layer 18, a light-emitting material layer 13', a second conductivity type semiconductor material layer 17', and a second electrode material layer 12' are sequentially formed on a substrate 14 using a metal-organic chemical vapor deposition process to form a light-emitting diode (LED) substrate. For example, the substrate 14 includes a sapphire substrate and a buffer layer, and the first conductivity type semiconductor layer 18 is formed on the buffer layer.

[0147] For example, such as Figure 12 As shown, the light-emitting diode mother chip is processed to include multiple light-emitting units. The first mask is used as a mask to etch and divide the light-emitting material layer 13', the second conductivity type semiconductor material layer 17' and the second electrode material layer 12' to form multiple discrete light-emitting layers 13, second conductivity type semiconductor layers 17 and second electrode layers 12, that is, to form multiple light-emitting units.

[0148] For example, such as Figure 13 As shown, a second mask is used as a mask to etch the first conductivity type semiconductor layer 18, so that a portion of the light-emitting layer 13, the second conductivity type semiconductor layer 17 and the second electrode layer 12 on the first conductivity type semiconductor layer 18 are etched away, and a portion of the first conductivity type semiconductor layer 18 is etched away to form a recess or step structure.

[0149] For example, such as Figure 14 As shown, a fourth photomask is used as a mask to etch the first conductive semiconductor layer 18, the light-emitting layer 13, the second conductive semiconductor layer 17, and the second electrode 12, and the etching extends to the substrate 14 to achieve the segmentation of the light-emitting diode chip.

[0150] For example, such as Figure 15 As shown, a first electrode 15 is formed on a first conductivity type semiconductor layer 18.

[0151] For example, such as Figure 16 As shown, a barrier layer 19 is deposited on the side of the second electrode 12 away from the substrate 14 to block the light-emitting layer 13, the second electrode 12, and the second conductivity type semiconductor layer 17 of adjacent light-emitting units. Specifically, the light-emitting layers 13 of adjacent light-emitting units are separated from each other by the barrier layer 19, the second electrodes 12 of adjacent light-emitting units are insulated from each other by the barrier layer 19, and the second conductivity type semiconductor layers 17 in adjacent light-emitting units are separated from each other by the barrier layer 19. The barrier layer 19 is also configured to isolate the first electrode 15 from the light-emitting layer 13, the second conductivity type semiconductor layer 17, and the second electrode 12. For example, contact pads 11 and 16 are formed on the barrier layer 19, with the contact pad 16 connected to the first electrode 15 being the first contact pad 16, and the contact pad 11 connected to the second electrode 12 being the second contact pad 11.

[0152] For example, Figure 15 andFigure 16 The diagram schematically shows the formation of a first electrode 15 followed by the formation of a first contact pad 16 connected to the first electrode 15. However, it is not limited to this, and the first electrode 15 and the first contact pad 16 can be formed simultaneously.

[0153] For example, after the contact pad is formed, a protective layer is formed on the side of the contact pad away from the substrate to protect the contact pad.

[0154] For example, such as Figure 4 As shown, after forming the protective layer, a pixel defining portion 150 with multiple openings 151 is patterned on the side of the substrate 14 away from the light-emitting layer 13. Then, a first color conversion layer 210 and a second color conversion layer 310 are formed in the openings 151 of the second color light-emitting unit 200 and the third color light-emitting unit 300, respectively. For example, a color conversion material is formed in the openings 151 by printing. For example, the color conversion material may include quantum dot materials or fluorescent materials. For example, scattering particles 110 may be formed in the openings 151 of the first color light-emitting unit 100. For example, a transparent material including scattering particles 110 may be formed in the openings 151 of the first color light-emitting unit 100, such as photoresist, acrylic system, or silicone system. The scattering particles 110 may include materials such as titanium dioxide (TiO2), silicon dioxide (SiO2), barium sulfate (BaSO4), and zirconium dioxide (ZrO2), and the size of the scattering particles 110 may be 200-300 nanometers.

[0155] For example, such as Figure 4 As shown, after the color conversion layer is formed, a color filter layer 30 is formed on the side of the color conversion layer away from the substrate 14.

[0156] For example, Figure 17 This is a partial cross-sectional structural diagram of a display substrate provided according to an embodiment of the present disclosure. Figure 17 The display substrate shown is Figure 4 The difference in the stacked film structure of the display substrate shown lies in the structure of the first conductivity type semiconductor layer 18 on the side away from the light-emitting layer 13, while Figure 17 and Figure 4 The substrate 14 of the display substrate shown may include a second contact pad 11, a second electrode 12, a second conductivity type semiconductor layer 17, a light-emitting layer 13 and a first conductivity type semiconductor layer 18 stacked sequentially on the side facing the light-emitting layer 13. Multiple light-emitting units in each light-emitting diode chip share the first conductivity type semiconductor layer 18, the first electrode 15 and the first contact pad 16. Figure 17 The display substrate shown is Figure 4 The difference in the display substrate shown is that a plurality of grooves 141 are provided on the side of the substrate 14 away from the light-emitting layer 13.

[0157] For example, such as Figure 17 As shown, a plurality of grooves 141 are provided on the side of the sapphire layer 140 of the substrate 14 away from the light-emitting layer 13.

[0158] For example, such as Figure 17 As shown, the depth of at least one groove 141 is greater than 10 micrometers. For example, the depth of each groove 141 can be greater than half the thickness of the sapphire layer 140. For example, the ratio of the depth of at least one groove 141 to the thickness of the sapphire layer 140 can range from 0.5 to 0.9, for example, from 0.6 to 0.8.

[0159] For example, the sapphire layer 140 can be 60 micrometers thick, and the groove 141 can be 55 micrometers deep.

[0160] For example, such as Figure 17 As shown, each light-emitting unit is provided with a groove 141, and in each light-emitting unit, the groove 141 overlaps with the light-emitting layer 13. For example, in each light-emitting unit, the groove 141 and the light-emitting layer 13 are arranged facing each other.

[0161] For example, at least one recess 141 has a light-shielding layer 142 on its inner sidewall. The "inner sidewall" of the recess, as mentioned above and subsequently, refers to a ring of sidewalls on the inner side of the recess, excluding the bottom wall opposite the sapphire layer. The light-shielding layer is used to block light emitted from the light-emitting layers of other light-emitting units from entering the recess.

[0162] For example, each groove 141 has a light-shielding layer 142 on its inner sidewall. For example, the light-shielding layer 142 can be a reflective layer, so that while blocking the light of other light-emitting units, it can efficiently reflect the light incident on the reflective layer.

[0163] For example, such as Figure 17 As shown, a first color conversion layer 210 is disposed in the groove 141 of the second color light-emitting unit, and a second color conversion layer 310 is disposed in the groove 141 of the third color light-emitting unit. For example, scattering particles 110 can be disposed in the groove 141 of the first color light-emitting unit, such as a transparent material including scattering particles 110, such as photoresist.

[0164] For example, such as Figure 17 As shown, there is a first interval D between the light-emitting areas of adjacent light-emitting units. For example, the length of the first interval D can be d. 11 +d 12 -d 13 The edges of adjacent light-emitting units that are close to each other have a second spacing D'. Along the arrangement direction of the light-emitting units, the orthographic projections of the first spacing D and the second spacing D' onto the surface of the substrate 140 facing the light-emitting layer can completely overlap. This complete overlap can mean that the overlap rate between the two is not less than 90%.

[0165] For example, as Figure 17 shown, the refractive index of the light-emitting layer 13 is 2.54, the refractive indices of the first conductive type semiconductor layer 18 and the buffer layer 14-1 are both 2.45, the refractive index of the sapphire layer 140 is 1.77, and the refractive indices of the first color conversion layer 210 and the second color conversion layer 310 are 1.5. When the first color light emitted from the light-emitting layer 13 at the edge of the barrier opening of each color light-emitting unit passes through each film layer located between the color conversion layer and the light-emitting layer 13, total reflection occurs when the incident light angle satisfies the total reflection critical angle. When the incident angle of the light emitted from the light-emitting layer at the interface of each film layer is at least the total reflection critical angle, the color mixing ratio of the light emitted from adjacent light-emitting units during the process of passing through the first conductive type semiconductor layer, the buffer layer, and the sapphire layer can be minimized.

[0166] In the present disclosure, the depth and width of the groove can be designed based on the position of the edge of the light-emitting layer, the thickness of each film layer between the color conversion layer and the light-emitting layer, and the position of the pixel defining portion opening. For example, the cross-sectional shape of the groove 141 intercepted by a plane perpendicular to the main surface of the substrate can be trapezoidal or rectangular, and the embodiments of the present disclosure do not limit this. For example, when the cross-sectional shape of the groove 141 is rectangular, the width of the groove can be 50 micrometers. For example, when the cross-sectional shape of the groove 141 is trapezoidal, the length of the bottom side of the trapezoid closer to the light-emitting layer can be 50 micrometers.

[0167] For example, as Figure 17 shown, the incident angle of the light ray 132 emitted from the edge of the light-emitting layer 13 of each color light-emitting unit during total reflection at the interface between the first conductive type semiconductor layer 18 and the sapphire layer 140 is the total reflection critical angle θ 11 , and the incident angle of the light ray 132 emitted from the edge of the light-emitting layer 13 of each color light-emitting unit during total reflection at the interface between the sapphire layer 140 and the color conversion layer is the total reflection critical angle θ 12 . The lower edge of the groove 141 can be determined by the total reflection critical angle θ 12 . For example, the lower edge of the groove 141 can be the position where the incident angle of the light ray emitted from the edge of the light-emitting layer of the adjacent light-emitting unit when it enters the edge of the color conversion layer is exactly the total reflection critical angle θ 12 , or a position closer to the center of the light-emitting area than the above position to reduce color mixing.

[0168] According to the refractive index n of each film layer above and the formula sinθ c satisfied by the total reflection critical angle θ c =n2 / n1, n2 < n1, the calculated total reflection critical angle θ 11 is approximately 46°, and the total reflection critical angle θ 12 is approximately 58°.

[0169] For example, asFigure 18 As shown, the thickness of the first conductivity type semiconductor layer 18 and the buffer layer 14-1 can both be 2 micrometers, and the thickness of the remaining portion of the sapphire layer 140, excluding the groove 141, can be 5 micrometers. Based on the aforementioned critical angle θ for total internal reflection... 11 The total thickness H of the first conductivity type semiconductor layer 18 and the buffer layer 14-1, and the relationship d 11 =H*tanθ 11 d can be calculated 11 Approximately 4.14 micrometers, based on the remaining thickness h of the sapphire layer 140, the critical angle for total internal reflection θ2, and the relationship d. 12 =h*tanθ 12 The approximate value of d2 can be calculated to be 8 micrometers. Assume the inclination angle θ of the sidewall of groove 141 is... 13 If the angle is 5° and the depth of groove 141 is 55 micrometers, then d 13 Approximately 4.8 micrometers, the distance between the luminescent regions of adjacent luminescent units (d) 11 +d 12 -d 13 If the distance between the light-emitting areas of adjacent light-emitting units is approximately 7.34 micrometers, then the cross-color ratio between adjacent light-emitting units can be greatly reduced when the distance between the light-emitting areas of adjacent light-emitting units is not less than 8 micrometers.

[0170] Of course, when the thickness of each of the above-mentioned film layers changes, or when at least one of the tilt angle of the groove sidewall and the refractive index of the material changes, the distance between the light-emitting areas of the adjacent light-emitting units will also change.

[0171] By placing the color conversion layer in a groove in the substrate, compared to a substrate without a groove and the color conversion layer placed on the side of the substrate away from the light-emitting layer, the distance between the light-emitting units can be reduced to less than 10 micrometers under the condition of the lowest possible cross-color ratio (e.g., no more than 5%). This minimizes the impact of the spacing between adjacent light-emitting units on the size of the light-emitting diode chip, making it possible to achieve high pixel density in the display substrate.

[0172] In this disclosure, a groove is formed on the side of the substrate away from the light-emitting layer, a light-shielding layer is formed on the inner sidewall of the groove, and a color conversion layer is formed within the groove. This reduces the distance between the light-emitting layer and the color conversion layer, thereby reducing the distance between the light-emitting areas of adjacent light-emitting units. This is beneficial for reducing the size of the light-emitting diode chip and thus increasing the pixel density of the display substrate. For example, this disclosure provides a miniature light-emitting diode display substrate with high resolution and low crosstalk characteristics.

[0173] For example, Figure 18 This is a partial cross-sectional structural diagram of a display substrate provided according to an example embodiment of the present disclosure. For example... Figure 19As shown, a transparent filling layer 143 is provided in the bottom of the groove 141 of at least one of the second color light-emitting unit 200 and the third color light-emitting unit 300. For example, the transparent filling layer 143 is located inside the groove 141.

[0174] For example, the depth of the groove 141 can be 55 micrometers, the thickness of the transparent filler layer 143 can be 25 micrometers, and the thickness of the color conversion layer can be 30 micrometers. For example, the thickness of the color conversion layer can be equal to the thickness of the transparent filler layer. However, this disclosure is not limited to this; the thickness of the color conversion layer may also be no greater than the thickness of the transparent filler layer.

[0175] For example, a transparent filling layer 143 is provided in the bottom of the groove 141 of the first color light-emitting unit 100, the second color light-emitting unit 200 and the third color light-emitting unit 300.

[0176] For example, the transparent filler layer 143 is made of a hydrophilic material, such as a material that can have carboxyl groups, hydroxyl groups or ester groups added.

[0177] In this disclosure, a transparent filling layer is disposed within a groove containing quantum dot material. The thickness of the quantum dot material can be adjusted by regulating the thickness of the transparent filling layer, thereby adjusting the conversion efficiency of the quantum dot material. For example, when the display substrate is used in applications requiring high brightness, the quantum dot material is thicker; when the display substrate is used in applications requiring low brightness, the quantum dot material is thinner.

[0178] For example, Figure 19 This is a partial cross-sectional structural diagram of a display substrate provided according to an example embodiment of the present disclosure. For example... Figure 19 As shown, a blocking portion 144 is provided on the side of the gap between the grooves 141 of adjacent light-emitting units away from the light-emitting layer 13. The material of the blocking portion 144 includes a hydrophobic material, such as a fluorine-containing material. Since fluorine has high polarity, it will migrate to the surface, causing the quantum dot material to slide into the groove when it falls onto the blocking portion.

[0179] Figure 20 The illustration shows that a blocking portion and a transparent filler layer are provided in the display substrate at the same time, but it is not limited to this. Only a blocking portion or only a transparent filler layer may be provided.

[0180] For example, the cross-sectional shape of the blocking portion 144 cut by a plane perpendicular to the main surface of the substrate can be trapezoidal, rectangular, or semi-circular.

[0181] For example, if the spacing between adjacent light-emitting units is very small, and it is not easy to control the color transfer material (such as quantum dot material) to accurately enter the groove through the printing process, a blocking part 144 can be provided on the side of the gap between the grooves of adjacent light-emitting units away from the light-emitting layer 13. The material of the blocking part 144 includes a hydrophobic material, which facilitates the diffusion of quantum dot material and controls the size of the quantum dot region, and can better avoid the risk of color mixing.

[0182] For example, the material of the blocking portion 144 can be white, black, or colorless photoresist.

[0183] For example, Figures 17 to 19 for Figure 20 A schematic diagram of the planar arrangement of the light-emitting areas of multiple light-emitting units in any of the shown display substrates. (See attached diagram.) Figure 17 As shown, in each LED chip, the light-emitting areas of multiple light-emitting units are arranged along a third direction. For example, the light-emitting areas 101 of the first color light-emitting unit, 201 of the second color light-emitting unit, and 301 of the third color light-emitting unit are arranged along a third direction. The second contact pad 15 is located on one side of the light-emitting areas of the multiple light-emitting units in a fourth direction, and the third and fourth directions intersect. For example, one of the third and fourth directions can be parallel to the first direction, and the other can be parallel to the second direction, but it is not limited to this. Figure 20 The diagram illustrates that the third direction is the first direction, i.e., the X direction, and the fourth direction is the second direction, i.e., the Y direction.

[0184] For example, such as Figure 20 As shown, the second contact pads 11 of the multiple light-emitting units are arranged along a third direction, that is, the second contact pads 11-1 of the first color light-emitting unit, the second contact pads 11-2 of the second color light-emitting unit and the second contact pads 11-3 of the third color light-emitting unit are arranged along a third direction, and the second contact pads 15 are located on one side of the multiple first contact pads 11 in the fourth direction.

[0185] For example, such as Figure 20 As shown, the light-emitting area of ​​each light-emitting unit may overlap with the second contact pad 11, and may also overlap with the portion of the light-emitting area that is far from the first contact pad 15 to ensure that the distance between the first contact pad and the second contact pad meets the safety distance requirement. However, this is not the only possibility; the light-emitting area of ​​each light-emitting unit may also not overlap with the second contact pad 11.

[0186] For example, such as Figure 20As shown, in each LED chip, the shortest distance between the edges of the light-emitting areas of adjacent light-emitting units is no greater than 50 micrometers. For example, in each LED chip, the shortest distance between the edges of the light-emitting areas of adjacent light-emitting units is no greater than 30 micrometers. In each LED chip, the shortest distance between the edges of the light-emitting areas of adjacent light-emitting units is no greater than 15 micrometers. In each LED chip, the shortest distance between the edges of the light-emitting areas of adjacent light-emitting units is no greater than 10 micrometers.

[0187] For example, such as Figure 20 As shown, the size of the light-emitting area of ​​each light-emitting unit along the X direction can be 50 micrometers and the size along the Y direction can be 100 micrometers; the second contact pad 11 of each light-emitting unit can be square and the side length can be 50 micrometers; the size of the first contact pad 15 along the X direction can be 166 micrometers and the size along the Y direction can be 30 micrometers.

[0188] For example, such as Figure 20 As shown, the dimension of the LED chip along the X direction can be 226 micrometers. For example, the LED chip can be square, then the side length D1 of the LED chip can be 226 micrometers.

[0189] For example, this example is not limited to multiple light-emitting units in each LED chip. Figures 6 to 10 The arrangement shown can also be used for Figure 21 The arrangement shown is designed to further reduce the size of the LED chips while maintaining a low crosstalk ratio, thereby increasing the pixel density of the display substrate.

[0190] For example, in a plane parallel to the first and second directions (or in a plane parallel to the third and fourth directions), the maximum size of the LED chip is no greater than 400 micrometers. The aforementioned "maximum size" can refer to the length of the diagonal, side length, or diameter of the planar shape of the LED chip. For example, when the LED chip is polygonal, the maximum size of each LED chip parallel to the aforementioned plane can be the length of the polygon's diagonal. For example, when the LED chip is circular, the maximum size of each LED chip parallel to the aforementioned plane can be its diameter.

[0191] For example, the pixel density of the aforementioned display substrate can reach over 100. For example, by reducing the area of ​​the light-emitting region of the light-emitting unit, the size of the LED chip can be further reduced. For example, if the size of the light-emitting region of the light-emitting unit is 20μm*80μm, the size of the LED chip can be reduced to 136 micrometers, and the pixel density of the display substrate including this LED chip is approximately 200, greatly improving the application level of miniature LED display products. For example, LED chips can be directly bonded onto silicon-based circuit boards, thereby achieving a display substrate with high brightness and high pixel density.

[0192] For example, Figure 21 This is a partial cross-sectional structural diagram of a display substrate provided according to an embodiment of the present disclosure. Figure 17 and Figure 21 The difference in the stacked film structure of the display substrate shown is that the plurality of grooves 141 of the substrate 14 are at least partially disposed between adjacent light-emitting units 20, and at least the inner sidewall of each groove 141 is provided with a light-shielding material 145. For example, a portion of the plurality of grooves 141 is disposed between adjacent light-emitting units, and another portion is disposed between adjacent light-emitting diode chips.

[0193] For example, the groove 141 can be filled with light-shielding material 145. Alternatively, the groove 141 may only have light-shielding material on its bottom and inner sidewalls, or the groove 141 may not be filled with light-shielding material 145. The light-shielding material is used to block light emitted from the light-emitting layers of other light-emitting units from entering the color conversion layer.

[0194] For example, light-blocking materials can be metallic or light-absorbing materials.

[0195] Because the sapphire layer is relatively thick (e.g., greater than 60 micrometers), cross-color transmission between adjacent light-emitting units is likely. For example, light emitted from the light-emitting layer of a second-color light-emitting unit can easily enter the color conversion layer of a third-color light-emitting unit, or vice versa. Therefore, by creating grooves in the substrate and placing light-shielding materials with a light-shielding effect in the grooves, the cross-color transmission ratio between adjacent light-emitting units can be minimized, and the distance between the light-emitting areas of adjacent light-emitting units can be reduced, thereby minimizing the size of the LED chip.

[0196] For example, such as Figure 21As shown, the refractive index of the light-emitting layer 13 is 2.54, the refractive indices of the first-conductive-type semiconductor layer 18 and the buffer layer 14-1 are both 2.45, the refractive index of the sapphire layer 140 is 1.77, and the refractive indices of the first color conversion layer 210 and the second color conversion layer 310 are 1.5. When the first color light emitted from the light-emitting layer 13 at the edge of the barrier opening of each color light-emitting unit passes through each film layer located between the color conversion layer and the light-emitting layer 13, total reflection will occur when the incident light angle satisfies the total reflection critical angle. When the incident angle of the light emitted from the light-emitting layer at the interface of each film layer is at least the total reflection critical angle, the color mixing ratio of the light emitted from adjacent light-emitting units during the process of passing through the first-conductive-type semiconductor layer, the buffer layer, and the sapphire layer can be minimized.

[0197] For example, as Figure 21 shown, the incident angle of the light ray 133 emitted from the edge of the light-emitting layer 13 of each color light-emitting unit during total reflection at the interface between the buffer layer 14-1 and the sapphire layer 140 is the total reflection critical angle θ 21 , and the incident angle of the light ray 133 emitted from the edge of the light-emitting layer 13 of each color light-emitting unit during total reflection at the interface between the sapphire layer 140 and the color conversion layer is the total reflection critical angle θ 22 . According to the refractive index n of each of the above film layers and the total reflection critical angle θ c satisfying the formula sinθ c = n2 / n1, n2 < n1, the total reflection critical angle θ 21 is approximately 46°, and the total reflection critical angle θ 22 is approximately 58°. For example, as Figure 21 shown, the position of the bottom edge of the groove 141 can be set according to the total reflection critical angle θ 22 at the interface between the sapphire layer 140 and the color conversion layer during total reflection.

[0198] For example, as Figure 21 shown, the thicknesses of the first-conductive-type semiconductor layer 18 and the buffer layer 14-1 can both be 2 μm, the thickness of the sapphire layer 140 can be 60 μm, and the thickness of the remaining part of the sapphire layer 140 except for the groove 141 is 5 μm. According to the above total reflection critical angle θ 21 , the total thickness H of the first-conductive-type semiconductor layer 18 and the buffer layer 14-1, and the relationship d 21 = H * tanθ 21 d can be calculated to be approximately 4.2 μm. According to the thickness h of the remaining part of the sapphire layer 140, the total reflection critical angle θ <( 21 and the relationship d 22 = h * tanθ 22 d can be calculated to be approximately 4.2 μm. 22It can be calculated that d2 is approximately 8 micrometers. Therefore, the length of the bottom edge of the groove (d) 21 +d 22 The length of the groove bottom edge is approximately 12 micrometers, which can greatly reduce optical crosstalk when the remaining thickness of the sapphire layer is 5 micrometers.

[0199] Of course, when the thickness of the above-mentioned film layers changes, or when the material changes and the refractive index changes, the distance between the light-emitting areas of the adjacent light-emitting units that does not cause cross-coloring will also change.

[0200] For example, such as Figure 4 As shown, a pixel limiting portion 150 is provided on the side of the substrate 14 away from the light-emitting layer 13. In this example, the pixel limiting portion 150 can be connected with... Figure 21 The pixel defining portions shown have the same features. For example, the cross-sectional shape of the pixel defining portion located between adjacent light-emitting units can be trapezoidal or rectangular, and the embodiments disclosed herein do not limit this.

[0201] For example, such as Figure 21 As shown, at least a portion of the pixel defining portion 150 is stacked with the light-shielding material 145. For example, the pixel defining portion 150 overlaps with the light-shielding material layer 145 along a direction perpendicular to the plane of the first direction and the second square.

[0202] For example, the ratio of the area of ​​the pixel defining portion 150 facing the light-shielding material layer 145 to the area of ​​the light-shielding material layer 145 facing the pixel defining portion 150 can be 0.9 to 1.1. For example, the area of ​​the pixel defining portion 150 facing the light-shielding material layer 145 can be 5% larger than the area of ​​the light-shielding material layer 145 facing the pixel defining portion 150.

[0203] Figure 22 The illustration shows that the cross-section of the groove is rectangular, but it is not limited to this and can also be trapezoidal or other shapes.

[0204] For example, Figure 22 This is a schematic diagram illustrating the structure for forming a groove in the sapphire layer of a light-emitting diode (LED) chip, and forming a color conversion layer within the groove. (See diagram for example.) Figure 22 As shown, after the first contact pad 16 and the second contact pad 11 are formed, the sapphire layer 140 of the light-emitting diode chip is thinned, for example, by grinding the sapphire layer 140 to a thickness of 60 micrometers. For example, after grinding the sapphire layer 140, a plurality of grooves 141 are formed on the substrate 14, for example, on the side of the sapphire layer 140 away from the light-emitting layer 13. For example, after forming the grooves 141, a color conversion layer can be formed within the grooves 141. Figure 19The illustration shows the formation of a color conversion layer within a groove, but it is not limited to this. Alternatively, a light-shielding layer and a filling layer can be formed within the groove first, followed by the formation of the color conversion layer. For example, after forming the color conversion layer, it can be formed on the side of the sapphire layer 140 away from the light-emitting layer 13. Figure 17 The blocking portion 144 shown is formed on the side of the color conversion layer away from the light-emitting layer 13. Figure 23 The color filter layer 30 is shown.

[0205] For example, Figure 23 This is a schematic diagram illustrating the structure for forming a groove in the sapphire layer of a light-emitting diode chip, and forming a light-shielding material within the groove. (See diagram for example.) Figure 21 As shown, after the first contact pad 16 and the second contact pad 11 are formed, the sapphire layer 140 of the light-emitting diode chip is processed, for example, by grinding the sapphire layer 140 to a thickness of 60 micrometers. For example, after grinding the sapphire layer 140, a plurality of grooves 141 are formed on the bottom 14, for example, on the side of the sapphire layer 140 away from the light-emitting layer 13. For example, after forming the grooves 141, a light-shielding material 145 can be formed in the grooves 141.

[0206] For example, such as Figure 21 As shown, after forming the light-shielding material 145, a pixel defining portion 150 having multiple openings 151 can be patterned on the side of the light-shielding material 145 away from the light-emitting layer 13. For example, a first color conversion layer 210 and a second color conversion layer 310 can be formed in the openings 151 of the second color light-emitting unit 200 and the third color light-emitting unit 300, respectively, and a color conversion material can be formed in the openings 151, for example, by printing. For example, the color conversion material may include quantum dot material or fluorescent material. For example, scattering particles 110 can be formed in the openings 151 of the first color light-emitting unit 100, for example, a transparent material including scattering particles 110, such as photoresist, can be formed in the openings 151 of the first color light-emitting unit 100.

[0207] For example, such as ​ As shown, after the color conversion layer is formed, a color filter layer 30 is formed on the side of the color conversion layer away from the substrate 14.

[0208] Another embodiment of this disclosure provides a display device including any of the above-described display substrates.

[0209] In the display device provided in this disclosure, on the one hand, by dividing each light-emitting diode chip into segments so that the same light-emitting diode chip emits at least two different colors of light, the high pixel density requirement of the display panel can be achieved; on the other hand, the multiple light-emitting units included in each light-emitting diode chip share a first electrode, which can maximize the effective light-emitting area of ​​each light-emitting unit.

[0210] In the display device provided in this disclosure, by arranging multiple light-emitting units in a triangular pattern in the light-emitting diode chip, the cross-color ratio of different color light-emitting units can be greatly reduced while the pitch of the light-emitting diode chip can be set to be smaller.

[0211] In the display device provided in this disclosure, multiple light-emitting units emitting different colors of light are arranged in the same light-emitting diode chip, and the positions of the light-emitting areas and contact pads of the multiple light-emitting units are set. This can reduce the cross-color ratio between adjacent light-emitting units and increase the pixel density of the display substrate. In addition, by controlling the light-emitting layers of different light-emitting units to emit the same intensity of the first color light, it can be ensured that the lifespan of the materials in different color conversion layers is approximately the same. At this time, white balance is achieved by adjusting the light-emitting area (aperture ratio) of the different color light-emitting units.

[0212] In the display device provided in this disclosure, a groove is provided on the side of the substrate away from the light-emitting layer, a light-shielding layer is provided on the inner sidewall of the groove, and a color conversion layer is provided in the groove. This can reduce the distance between the light-emitting layer and the color conversion layer, thereby reducing the distance between the light-emitting areas of adjacent light-emitting units. This is beneficial for reducing the size of the light-emitting diode chip and thus increasing the pixel density of the display device.

[0213] The display device provided in this disclosure can be a miniature light-emitting diode display device with crosstalk prevention and high resolution characteristics.

[0214] For example, the display device provided in this embodiment may further include an array substrate for providing electrical signals to a light-emitting diode (LED) chip. Specifically, the array substrate may include a driving circuit and bonding electrodes. The bonding electrodes are configured to be connected one-to-one with the first and second electrodes of the LED chip. Specifically, the bonding electrodes can be directly connected to the first and second electrodes of the LED chip using a connecting material (e.g., a low-melting-point metal or alloy, or anisotropic conductive adhesive). Alternatively, the bonding electrodes can be connected to the first and second contact pads of the LED chip using a connecting material (e.g., a low-melting-point metal or alloy, or anisotropic conductive adhesive). Each light-emitting unit can be controlled by a separate driving circuit. The driving circuit can be a 2T1C structure, consisting of a light-emitting control transistor, a driving transistor, and a storage capacitor; this embodiment includes, but is not limited to, this. For example, the driving circuit can also be a 5T1C, 6T1C, 7T1C, or 8T2C structure.

[0215] The following points need to be explained:

[0216] (1) The accompanying drawings of the embodiments of this disclosure only involve the structures involved in the embodiments of this disclosure, and other structures can be referred to the general design.

[0217] (2) Where there is no conflict, features of the same embodiment and different embodiments of this disclosure may be combined with each other.

[0218] The above description is merely an exemplary embodiment of this disclosure and is not intended to limit the scope of protection of this disclosure, which is determined by the appended claims.

Claims

1. A display substrate, comprising: Multiple light-emitting diode (LED) chips are provided, each LED chip comprising multiple light-emitting units that emit different colors of light. Each light-emitting unit includes a first electrode, a light-emitting layer, a substrate, and a second electrode. The substrate is located on the side of the light-emitting layer away from the second electrode. In each LED chip, the plurality of light-emitting units share the substrate and the first electrode. The light-emitting layers of the plurality of light-emitting units emit light of the same color, and at least one light-emitting unit further includes a first color conversion layer located on the side of the substrate away from the light-emitting layer, to convert the first color light emitted by the light-emitting layer into a second color light. The substrate includes a plurality of grooves that are recessed from the surface of the substrate away from the light-emitting layer toward the light-emitting layer, and the first color conversion layer is located within the grooves. A transparent filling layer is provided at the bottom of the groove, and the first color conversion layer is located on the side of the transparent filling layer away from the bottom of the groove and is in direct contact with the transparent filling layer so as to adjust the thickness of the first color conversion layer through the transparent filling layer.

2. The display substrate according to claim 1, wherein, Each light-emitting unit also includes a first contact pad and a second contact pad disposed on the same layer, wherein the first contact pad is connected to the first electrode and the second contact pad is connected to the second electrode; Each light-emitting diode chip includes a first color light-emitting unit, a second color light-emitting unit, and a third color light-emitting unit. The first color light-emitting unit is configured to emit the first color light. The second color light-emitting unit further includes a first color conversion layer located on the side of the substrate away from the light-emitting layer and emits the second color light. The third color light-emitting unit further includes a second color conversion layer located on the side of the substrate away from the light-emitting layer to convert the first color light emitted by the light-emitting layer into the third color light. The second color conversion layer is located in the groove.

3. The display substrate according to claim 2, wherein, In each LED chip, the line connecting the geometric centers of the light-emitting areas of the first color light-emitting unit, the second color light-emitting unit, and the third color light-emitting unit forms a first triangle, and the ratio of the shortest distance between the edges of the light-emitting areas of different color light-emitting units is 0.6 to 1.

5.

4. The display substrate according to claim 3, wherein, The light-emitting areas of the plurality of light-emitting units in each LED chip are distributed within a rectangular area, and the light-emitting areas of the first color light-emitting unit, the second color light-emitting unit, and the third color light-emitting unit are respectively located at the three right angles of the rectangular area.

5. The display substrate according to claim 4, wherein, In each LED chip, the second contact pad of the first color light-emitting unit, the second contact pad of the second color light-emitting unit, and the second contact pad of the third color light-emitting unit are respectively distributed at the three right-angle positions of the rectangular area, and the first contact pad is located at the fourth right-angle position of the rectangular area.

6. The display substrate according to claim 3, wherein, The first triangle is an acute triangle.

7. The display substrate according to claim 6, wherein, In each LED chip, the geometric center line connecting the second contact pad of the first color light-emitting unit, the second contact pad of the second color light-emitting unit, and the second contact pad of the third color light-emitting unit forms a second triangle, and at least a portion of the first contact pad is located within the second triangle.

8. The display substrate according to any one of claims 2-7, wherein, The area of ​​the light-emitting region of the second color light-emitting unit and the area of ​​the light-emitting region of the third color light-emitting unit are both larger than the area of ​​the light-emitting region of the first color light-emitting unit.

9. The display substrate according to any one of claims 3-7, wherein, The plurality of light-emitting diode chips are arranged in an array along a first direction and a second direction, and the pitch of the plurality of light-emitting diode chips along at least one of the first direction and the second direction is not greater than 400 micrometers.

10. The display substrate according to claim 2, wherein, The substrate includes a sapphire layer, and the groove is located on the sapphire layer, the depth of which is greater than half the thickness of the sapphire layer.

11. The display substrate according to claim 10, wherein, At least one groove has a depth greater than 10 micrometers.

12. The display substrate according to claim 10 or 11, wherein, Each light-emitting unit is provided with a groove, and in each light-emitting unit, the groove overlaps with the light-emitting layer, and at least one groove has a light-shielding layer on its inner sidewall; The first color conversion layer is disposed in the groove of the second color light-emitting unit, and the second color conversion layer is disposed in the groove of the third color light-emitting unit.

13. The display substrate according to claim 12, wherein, The transparent filling layer is disposed at the bottom of the groove of at least one of the second color light-emitting unit and the third color light-emitting unit.

14. The display substrate according to claim 12, wherein, A blocking portion is provided on the side of the gap between the grooves of adjacent light-emitting units away from the light-emitting layer, and the material of the blocking portion includes a hydrophobic material.

15. The display substrate according to claim 10 or 11, wherein, At least a portion of the plurality of grooves are disposed between adjacent light-emitting units, and at least the inner sidewall of each groove is provided with a light-shielding material.

16. The display substrate according to claim 15, wherein, A pixel defining portion is provided on the side of the substrate away from the light-emitting layer. The pixel defining portion includes multiple openings to define multiple light-emitting areas of the multiple light-emitting units. The first color conversion layer is disposed in the opening of the second color light-emitting unit, and the second color conversion layer is disposed in the opening of the third color light-emitting unit.

17. The display substrate according to claim 16, wherein, At least one groove is filled with the light-shielding material, and at least a portion of the pixel defining portion is stacked with the light-shielding material.

18. The display substrate according to claim 10 or 11, wherein, In each LED chip, the light-emitting areas of the plurality of light-emitting units are arranged along a third direction, and the second contact pad is located on the side of the light-emitting areas of the plurality of light-emitting units in a fourth direction, wherein the third direction and the fourth direction intersect.

19. The display substrate according to claim 10 or 11, wherein, In each LED chip, the shortest distance between the edges of the light-emitting areas of adjacent light-emitting units is no more than 50 micrometers.

20. The display substrate according to claim 10 or 11, wherein, The plurality of light-emitting diode chips are arranged in an array along a first direction and a second direction, and the pitch of the plurality of light-emitting diode chips along at least one of the first direction and the second direction is not greater than 300 micrometers.

21. The display substrate according to any one of claims 2-7, 10 and 11, wherein, The materials of the first color conversion layer and the second color conversion layer include quantum dot materials or fluorescent materials.

22. The display substrate according to claim 8, wherein, The first color light-emitting unit is a blue light-emitting unit, and one of the second color light-emitting unit and the third color light-emitting unit is a red light-emitting unit, and the other is a green light-emitting unit.

23. A display device comprising the display substrate according to any one of claims 1-22.

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