Pixel unit and display panel

Abstract

The utility model relates to a pixel unit and a display panel. Each pixel unit comprises a substrate, at least three light-emitting units with different colors and filling layers, wherein the light-emitting units are arranged on the substrate at intervals, and the filling layers are arranged among the light-emitting units. Wherein the non-light-emitting surfaces of the light-emitting units are provided with reflecting layers, and the heights of the reflecting layers on different light-emitting units are different. According to the technical scheme, the light utilization rate can be improved, and the low-power-consumption and high-brightness effects are achieved. In addition, by improving the height of the reflecting layer, the light pattern of the light-emitting unit can be improved, and therefore the large-view-angle color cast problem of the display screen is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductor display, in particular to a pixel unit and a display panel. Background Art

[0002] Micro LED, i.e. miniaturization and matrix technology of LED, has good stability, lifespan, and advantages in operating temperature. At the same time, micro LED also inherits the advantages of LED such as low power consumption, high color saturation, fast response speed, strong contrast, etc., and has great application prospects, such as micro LED display screen.

[0003] During the manufacturing process of the micro-LED display, the LEDs on the growth substrate need to be transferred and fixed to the back panel of the display. After being transferred and fixed to the back panel of the display, in order to reduce the reflection intensity of the circuit board to the ambient light, a common method is to fill the gaps between the chips with black glue, and then make a transparent sealing glue on the outermost layer. However, since the chip emits light in all directions, only the light from the surface that is not encapsulated by the black glue is emitted from the display to present the signal. The light from the other five light-emitting surfaces cannot pass through the black glue, resulting in loss. In order to achieve a high-brightness display, a larger current drive is required, resulting in higher power consumption. Utility Model Content

[0004] In view of the above-mentioned deficiencies in the prior art, the purpose of the present application is to provide a pixel unit and a display panel, aiming to solve the above-mentioned technical problems.

[0005] A pixel unit, comprising a substrate, light-emitting units of at least three different colors arranged on the substrate at intervals, and a filling layer arranged between the light-emitting units;

[0006] Wherein, a reflective layer is provided on the non-light emitting surface of the light emitting unit, and along a direction perpendicular to the extension direction of the substrate, the heights of the reflective layers on different light emitting units are different.

[0007] The above-mentioned pixel unit is used to present a pattern signal because a reflective layer of different heights is set on the non-light-emitting surface of the light-emitting units of three different colors, and the non-light-emitting surface can be the lower surface of the light-emitting unit and the five surfaces of the left, right, front and back of the light-emitting unit. The light beam is reflected once or multiple times by the reflective layer and finally emitted from the light-emitting surface of the light-emitting unit. In addition, since the height of the reflective layer of different light-emitting units is different. By adjusting the height of the reflective layer, the distribution of the light of the light-emitting units of three different colors at different angles can be adjusted. The higher the height of the reflective layer, the less light is distributed at a large viewing angle, thereby adjusting the problem of inconsistent brightness attenuation of the light-emitting units of three different colors at a large viewing angle and improving color deviation.

[0008] In one embodiment, the non-light-emitting surface includes a side surface and an electrode surface; wherein the electrode surface is opposite to the light-emitting surface, and the side surface is connected between the electrode surface and the light-emitting surface.

[0009] In one embodiment, the pixel unit includes light emitting units of three different colors, and the light emitting units of the three different colors are respectively a red light emitting unit, a green light emitting unit and a blue light emitting unit.

[0010] In one embodiment, the height of the reflective layer on the side of the red light-emitting unit is recorded as H1, the height of the reflective layer on the side of the green light-emitting unit is recorded as H2, and the height of the reflective layer on the side of the blue light-emitting unit is recorded as H3; wherein H1, H2, and H3 satisfy any of the following relationships:

[0011] H1<H2<H3; or,

[0012] H1<H2, H1<H3; or,

[0013] H2

[0014] H2

[0015] In one embodiment, the thickness of the reflective layer on different light emitting units is different.

[0016] In one embodiment, the thickness of the reflective layer on the side of the red light-emitting unit is recorded as T1, the thickness of the reflective layer on the side of the green light-emitting unit is recorded as T2, and the thickness of the reflective layer on the side of the blue light-emitting unit is recorded as T3; wherein T1, T2, and T3 satisfy any of the following relationships:

[0017] T1<T2<T3; or,

[0018] T1<T2, T1<T3; or,

[0019] T2<T1, T2<T3; or,

[0020] T2<T1<T3.

[0021] In one embodiment, the reflective layer is a distributed Bragg reflector structure or a high reflectivity photoresist material or a high refractive index photoresist material.

[0022] In one embodiment, the filling layer is black glue.

[0023] In one embodiment, it further includes:

[0024] A transparent packaging adhesive layer is disposed on each of the light-emitting units and the filling layer.

[0025] ​​Based on the same inventive concept, the present application also provides a display panel, which includes a plurality of pixel units and a driving circuit as described in any one of the above; wherein the driving circuit is electrically connected to each of the pixel units.

[0026] The above-mentioned display panel adopts the pixel units described in some of the above-mentioned embodiments, and the pixel units are provided with reflective layers of different heights on the non-light-emitting surfaces of the light-emitting units of three different colors, and the non-light-emitting surfaces can be the lower surface of the light-emitting unit and the left, right, front and back surfaces of the light-emitting unit. The light beams are reflected once or multiple times by the reflective layer, and finally emitted from the light-emitting surface of the light-emitting unit to present the pattern signal. In addition, since the reflective layers of different light-emitting units are of different heights. By adjusting the height of the reflective layer, the distribution of the light of the light-emitting units of three different colors at different angles can be adjusted. The higher the height of the reflective layer, the less light is distributed at a large viewing angle, thereby adjusting the problem of inconsistent brightness attenuation of the light-emitting units of three different colors at a large viewing angle, and improving the color deviation of the display panel. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a schematic structural diagram of a pixel unit in an embodiment of the present application;

[0028] Figure 2 is a schematic structural diagram of a pixel unit in another embodiment of the present application;

[0029] Figure 3 FIG. 4 is a schematic diagram of the structure of a pixel unit in another embodiment of the present application.

[0030] Description of reference numerals:

[0031] 10 - substrate; 210 - red light emitting unit; 220 - green light emitting unit; 230 - blue light emitting unit; 212 - first reflection layer; 222 - second reflection layer; 232 - third reflection layer; 30 - filling layer; 40 - transparent encapsulation glue layer. DETAILED DESCRIPTION

[0032] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present application are given in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thoroughly and comprehensively understood.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0034] As described in the background technology of this application, during the manufacturing process of the micro-LED display screen, it is necessary to transfer and fix the LEDs on the growth substrate to the back panel of the display screen. After being transferred and fixed to the back panel of the display screen, in order to reduce the reflection intensity of the circuit board to the ambient light, a common method is to make a filling black glue between the chips, and then make a transparent sealing glue on the outermost layer. However, since the chip emits light in all directions, only the light from the surface that is not encapsulated by the black glue is emitted from the display screen to present the signal. The light from the other five light-emitting surfaces cannot pass through the black glue and cause loss. In order to achieve a high-brightness display, a larger current drive is required, resulting in higher power consumption.

[0035] Based on this, the present application hopes to provide a solution that can solve the above-mentioned technical problems, the details of which will be described in the subsequent embodiments.

[0036] like Figure 1 As shown, the present application provides a pixel unit, which may include a substrate 10, at least three light-emitting units of different colors spaced apart on the substrate 10, and a filling layer 30 disposed between each of the light-emitting units; illustratively, for ease of description, this specific embodiment is subsequently described by taking the pixel unit including a red light-emitting unit 210, a green light-emitting unit 220, and a blue light-emitting unit 230 as an example.

[0037] A reflective layer (not shown) is disposed on the non-light emitting surface of the light emitting unit, and the heights of the reflective layer on different light emitting units are different along the extending direction perpendicular to the substrate 10 .

[0038] The above-mentioned pixel unit is used to present a pattern signal because a reflective layer of different heights is set on the non-light-emitting surface of the light-emitting units of three different colors, and the non-light-emitting surface can be the lower surface of the light-emitting unit and the five surfaces of the left, right, front and back of the light-emitting unit. The light beam is reflected once or multiple times by the reflective layer and finally emitted from the light-emitting surface of the light-emitting unit. In addition, since the height of the reflective layer of different light-emitting units is different. By adjusting the height of the reflective layer, the distribution of the light of the light-emitting units of three different colors at different angles can be adjusted. The higher the height of the reflective layer, the less light is distributed at a large viewing angle, thereby adjusting the problem of inconsistent brightness attenuation of the light-emitting units of three different colors at a large viewing angle and improving color deviation.

[0039] In one embodiment, the substrate 10 may be a temporary substrate, a growth substrate, or a driving backplane. This application does not limit this. Along the direction perpendicular to the extension direction of the substrate 10, that is, the vertical direction.

[0040] In one embodiment, the non-light-emitting surface includes a side surface and an electrode surface; wherein the electrode surface is opposite to the light-emitting surface, and the side surface is connected between the electrode surface and the light-emitting surface.

[0041] In one embodiment, the pixel unit includes three light emitting units of different colors, and the three light emitting units of different colors are red light emitting unit 210, green light emitting unit 220 and blue light emitting unit 230. The red light emitting unit 210, green light emitting unit 220 and blue light emitting unit 230 can be micro light emitting diodes or mini light emitting diodes.

[0042] In one embodiment, reference may be made to Figure 2 , the reflective layer on the side of the red light-emitting unit 210 is recorded as the first reflective layer 212, and the height of the first reflective layer 212 is recorded as H1, the reflective layer on the side of the green light-emitting unit 220 is recorded as the second reflective layer 222, and the height of the second reflective layer 222 is recorded as H2, and the reflective layer on the side of the blue light-emitting unit 230 is recorded as the third reflective layer 232, and the height of the third reflective layer 232 is recorded as H3; wherein H1, H2, and H3 satisfy any of the following relationships:

[0043] H1<H2<H3; or,

[0044] H1<H2, H1<H3; or,

[0045] H2

[0046] H2

[0047] ​​In other words, in this specific embodiment, the height H1 of the first reflective layer 212 may be the lowest, the height H2 of the second reflective layer 222 may be the second, and the height H3 of the third reflective layer 232 may be the highest; or, the height H1 of the first reflective layer 212 may be smaller than the height H2 of the second reflective layer 222 and the height H3 of the third reflective layer 232, but the height H2 of the second reflective layer 222 and the height H3 of the third reflective layer 232 may be the same or different. In different cases, the height H2 of the second reflective layer 222 may be greater than the height H3 of the third reflective layer 232, or the height H2 of the second reflective layer 222 may be smaller than the height H3 of the third reflective layer 232. The height H3 of the second reflective layer 222 is smaller than the height H1 of the first reflective layer 212 and the height H3 of the third reflective layer 232, but the height H1 of the first reflective layer 212 and the height H3 of the third reflective layer 232 can be the same or different. In different cases, the height H1 of the first reflective layer 212 can be greater than the height H3 of the third reflective layer 232, and the height H1 of the first reflective layer 212 can also be less than the height H3 of the third reflective layer 232; or, the height H2 of the second reflective layer 222 can be the lowest, the height H1 of the first reflective layer 212 is the second, and the height H3 of the third reflective layer 232 is the highest. This application does not make further restrictions on this. It should be understood that the height of each reflective layer can be designed according to the specific use scenario of the light-emitting unit, and this application does not make further details on this.

[0048] In one embodiment, the thickness of the reflective layer on different light-emitting units is different. Specifically, the reflective layer described in this embodiment mainly refers to the reflective layer arranged on the side of the light-emitting unit. The thickness of the reflective layer or the number of reflective interface layers is different, so that the light reflection and transmission capabilities are correspondingly different. The thicker the reflective layer is and the more interface layers there are, the stronger the reflection is and the less the transmission is. By adjusting the thickness of the side reflective layer or the number of interface layers of light-emitting units of different colors, the distribution of light emitted by light-emitting units of different colors at different angles can be adjusted, thereby adjusting the problem of inconsistent brightness attenuation of light-emitting units of different colors at a large viewing angle and improving color deviation. It can be understood that the thickness of the reflective layer or the number of interface layers in this specific embodiment can be designed according to the specific usage.

[0049] Further, see Figure 3 , the thickness of the reflective layer (first reflective layer 212) on the side of the red light-emitting unit 210 is recorded as T1, the thickness of the reflective layer (second reflective layer 222) on the side of the green light-emitting unit 220 is recorded as T2, and the thickness of the reflective layer (third reflective layer 232) on the side of the blue light-emitting unit 230 is recorded as T3; wherein T1, T2, and T3 satisfy any of the following relationships:

[0050] T1<T2<T3; or,

[0051] T1<T2, T1<T3; or,

[0052] T2<T1, T2<T3; or,

[0053] T2<T1<T3.

[0054] In other words, in this specific embodiment, the thickness T1 of the first reflective layer 212 may be the lowest, the thickness T2 of the second reflective layer 222 may be the second, and the thickness T3 of the third reflective layer 232 may be the highest; or, the thickness T1 of the first reflective layer 212 may be smaller than the thickness T2 of the second reflective layer 222 and the thickness T3 of the third reflective layer 232, but the thickness T2 of the second reflective layer 222 and the thickness T3 of the third reflective layer 232 may be the same or different. In different cases, the thickness T2 of the second reflective layer 222 may be greater than the thickness T3 of the third reflective layer 232, or the thickness T2 of the second reflective layer 222 may be less than the thickness T3 of the third reflective layer 232. The thickness T3 of the second reflective layer 222 is smaller than the thickness T1 of the first reflective layer 212 and the thickness T3 of the third reflective layer 232, but the thickness T1 of the first reflective layer 212 and the thickness T3 of the third reflective layer 232 can be the same or different. In different cases, the thickness T1 of the first reflective layer 212 can be greater than the thickness T3 of the third reflective layer 232, and the thickness T1 of the first reflective layer 212 can also be less than the thickness T3 of the third reflective layer 232; or, the thickness T2 of the second reflective layer 222 can be the lowest, the thickness T1 of the first reflective layer 212 is the second, and the thickness T3 of the third reflective layer 232 is the highest. This application does not make further restrictions on this. It should be understood that the height of each reflective layer can be designed according to the specific use scenario of the light-emitting unit, and this application does not make further details on this.

[0055] In one embodiment, the reflective layer may be a distributed Bragg reflector structure or a high reflectivity photoresist material or a high refractive index photoresist material.

[0056] In one embodiment, the filling layer 30 may be black glue.

[0057] In one embodiment, it further includes:

[0058] The transparent encapsulation adhesive layer 40 is disposed on each of the light-emitting units and the filling layer 30. By disposing the transparent encapsulation adhesive layer 40, the device can be protected from environmental influences and the reliability of the device can be improved.

[0059] Based on the same inventive concept, the present application also provides a display panel, which includes a plurality of pixel units and a driving circuit (not shown) as described above; wherein the driving circuit is electrically connected to each of the pixel units.

[0060] The above-mentioned display panel adopts the pixel units described in some of the above-mentioned embodiments, and the pixel units are provided with reflective layers of different heights on the non-light-emitting surfaces of the light-emitting units of three different colors, and the non-light-emitting surfaces can be the lower surface of the light-emitting unit and the left, right, front and back surfaces of the light-emitting unit. The light beams are reflected once or multiple times by the reflective layer, and finally emitted from the light-emitting surface of the light-emitting unit to present the pattern signal. In addition, since the reflective layers of different light-emitting units are of different heights. By adjusting the height of the reflective layer, the distribution of the light of the light-emitting units of three different colors at different angles can be adjusted. The higher the height of the reflective layer, the less light is distributed at a large viewing angle, thereby adjusting the problem of inconsistent brightness attenuation of the light-emitting units of three different colors at a large viewing angle, and improving the color deviation of the display panel.

[0061] Specifically, the driving circuit of the present application may be an active matrix circuit (AM) or a passive matrix circuit (PM) according to different driving modes. The display panel may be a Mini LED display panel, a Micro LED display panel, etc., or a backlight module applied to a passive light-emitting display device, and the passive light-emitting display device may be a liquid crystal display device.

[0062] In order to make the inventive concept of the present application easier for those skilled in the art to understand, the manufacturing process of any reflective layer is briefly described. It can be understood that the thickness or height can be adjusted accordingly by adjusting specific parameters.

[0063] ①First, take a COW (chip on wafer); apply photoresist on the COW. Taking negative photoresist as an example, this process can also be completed with positive photoresist. The thickness of the photoresist in this process can be combined with the subsequent mask exposure process to control the height of the reflective layer;

[0064] ② Expose the photoresist. In this process, the light-transmitting area of ​​the mask can have a transmittance of ≥90%, or different transmittance openings can be used to adjust the thickness of the photoresist in different areas.

[0065] ③ Development: Use NaOH or weak acid inorganic solvents and other degumming solutions to remove the photoresist from the chip sidewalls and pad surfaces where photoresist is not needed.

[0066] ④ Fabrication of the reflective layer. As mentioned before, the reflective layer material can be a DBR with a Bragg reflective structure, or can be a high-reflective or high-refractive-index photoresist material.

[0067] ⑤ Remove the photoresist. Use NMP or other degumming liquid to remove the photoresist together with the reflective layer covering the photoresist, leaving a reflective layer of the shape required for the chip, thereby realizing the production of the reflective layer.

[0068] This process is carried out by separately performing the above reflective layer process on light-emitting units of different colors that require different heights or thicknesses (number of interface layers), and by adjusting the thickness of the photoresist and the opening size of the light-transmitting area of ​​the mask, the production of different reflective layer heights and thicknesses for light-emitting units of different colors can be achieved.

[0069] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made according to the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A pixel unit, characterized in that: The pixel unit includes a substrate, light-emitting units of at least three different colors arranged on the substrate at intervals, and a filling layer arranged between the light-emitting units; Wherein, a reflective layer is provided on the non-light emitting surface of the light emitting unit, and along a direction perpendicular to the extension direction of the substrate, the heights of the reflective layers on different light emitting units are different.

2. The pixel unit according to claim 1, characterized in that: The non-light-emitting surface includes a side surface and an electrode surface; wherein the electrode surface is opposite to the light-emitting surface, and the side surface is connected between the electrode surface and the light-emitting surface.

3. The pixel unit according to claim 2, characterized in that: The pixel unit includes light emitting units of three different colors, and the light emitting units of the three different colors are respectively a red light emitting unit, a green light emitting unit and a blue light emitting unit.

4. The pixel unit according to claim 3, characterized in that: The height of the reflective layer on the side of the red light-emitting unit is recorded as H1, the height of the reflective layer on the side of the green light-emitting unit is recorded as H2, and the height of the reflective layer on the side of the blue light-emitting unit is recorded as H3; wherein H1, H2, and H3 satisfy any of the following relationships: H1<H2<H3; or, H1<H2, H1<H3; or, H2<H1, H2<H3; or, H2<H1<H3.

5. The pixel unit according to claim 3, characterized in that: Along a direction perpendicular to the extension direction of the substrate, the thickness of the reflective layer on different light-emitting units is different.

6. The pixel unit according to claim 5, characterized in that: The thickness of the reflective layer on the side of the red light-emitting unit is recorded as T1, the thickness of the reflective layer on the side of the green light-emitting unit is recorded as T2, and the thickness of the reflective layer on the side of the blue light-emitting unit is recorded as T3; wherein T1, T2, and T3 satisfy any of the following relationships: T1<T2<T3; or, T1<T2, T1<T3; or, T2<T1, T2<T3; or, T2<T1<T3.

7. The pixel unit according to any one of claims 1 to 6, characterized in that: The reflective layer is a distributed Bragg reflector structure or a high-reflectivity photoresist material or a high-refractive-index photoresist material.

8. The pixel unit according to any one of claims 1 to 6, characterized in that: The filling layer is black glue.

9. The pixel unit according to any one of claims 1 to 6, characterized in that: Also includes: A transparent packaging adhesive layer is disposed on each of the light-emitting units and the filling layer.

10. A display panel, characterized in that: The display panel comprises a plurality of pixel units and a driving circuit as described in any one of claims 1 to 9; wherein the driving circuit is electrically connected to each of the pixel units.

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