CN116978894A - Display device - Google Patents

Abstract

The invention discloses a display device, which includes: a driving substrate and a plurality of light-emitting units electrically connected to the driving substrate. The light-emitting units each include a light-emitting chip electrically connected to the driving substrate on one side close to the driving substrate. At least part of the light-emitting units further includes a light-emitting chip located on the side of the driving substrate. A light-transmitting matrix layer is provided on a side of the light-emitting chip away from the driving substrate; the light-transmitting matrix layer includes a plurality of nanopores, and the nanopores of the light-transmitting matrix layer of some light-emitting units are filled with color conversion materials. By replacing the light-emitting units with low luminous efficiency with a light-transmitting matrix layer on the light-emitting side of the light-emitting chip, and filling the nanopores of the light-transmitting matrix layer with color conversion materials, the luminous efficiency of each light-emitting unit in the display device can be improved. Providing a light-transmitting matrix layer separately for forming nanopores can avoid directly forming nanopores in the light-emitting chip, which will affect the light extraction efficiency of the light-emitting chip. Nanopores can also improve light extraction efficiency.

Description

a display device

Technical field

The present invention relates to the field of display technology, and in particular, to a display device.

Background technique

Self-luminous display devices have the advantages of not requiring a backlight module, simple device structure, and lower dark field brightness, and have become the focus of research in the display field.

Light Emitting Diode (LED) display technology refers to the use of light-emitting diodes as light-emitting devices for direct image display. LED display devices usually use three primary color light-emitting chips for full-color display.

Three-primary color light-emitting chips are generally made of different semiconductor materials. In particular, AlGaInP-based red light-emitting chips have low efficiency, brittle texture, and poor yield. Especially when the size is reduced to the micron level, the efficiency drops sharply. In addition, the refractive index of the epitaxial material of the light-emitting chip is greatly different from that of air and substrate materials. The light emitted from the light-emitting chip is prone to total reflection at the interface between the high-refractive index material and the low-refractive index material, resulting in luminescence. The light generated by the chip propagates in the form of a waveguide within the epitaxial layer film and is eventually reabsorbed by the epitaxial layer, thus limiting the light extraction efficiency of the light-emitting chip.

Contents of the invention

In some embodiments of the present invention, the display device includes: a driving substrate and a plurality of light-emitting units electrically connected to the driving substrate. The light-emitting units each include: a light-emitting chip electrically connected to a side close to the driving substrate. At least some of the light-emitting units also include : The light-transmitting matrix layer is located on the side of the light-emitting chip away from the driving substrate; the light-transmitting matrix layer includes a plurality of nanopores, and the nanopores of the light-transmitting matrix layer of some light-emitting units are filled with color conversion materials. By replacing the light-emitting units with low luminous efficiency with a light-transmitting matrix layer on the light-emitting side of the light-emitting chip, and filling the nanopores of the light-transmitting matrix layer with color conversion materials, the luminous efficiency of each light-emitting unit in the display device can be improved. Setting up a light-transmitting matrix layer separately for forming nanopores can avoid directly forming nanopores in the light-emitting chip, which will affect the light extraction efficiency of the light-emitting chip. After the light emitted from the light-emitting chip is incident on the light-transmitting matrix layer, due to the distribution of nanometers, the light can be emitted in all directions through the nanopores, thereby destroying the total reflection condition when the light is emitted outward and improving the light extraction efficiency.

In some embodiments of the present invention, the colors of the light emitted by the light-emitting chips included in the light-emitting unit may be different. Each light-emitting unit serves as a sub-pixel. In order to achieve full-color display, the light-emitting unit is divided into a red light-emitting unit, a green light-emitting unit and a blue light-emitting unit. Lighting unit. The red light-emitting unit, the green light-emitting unit and the blue light-emitting unit are repeatedly arranged in a set order. The red light-emitting unit acts as a red sub-pixel, the green light-emitting unit acts as a green sub-pixel, and the blue light-emitting unit acts as a blue sub-pixel. The adjacent one A red light-emitting unit, a green light-emitting unit and a blue light-emitting unit constitute a pixel unit. The green light-emitting unit and the blue light-emitting unit only include light-emitting chips. The red light-emitting unit includes a light-emitting chip and a light-transmitting matrix layer, and the nanopores of the light-transmitting matrix layer are filled with red conversion materials. The light-emitting chip included in the green light-emitting unit is a green LED, the light-emitting chip included in the blue light-emitting unit and the red light-emitting unit is a blue LED chip. The green LED chip emits green light, the blue LED chip emits blue light, and the blue LED chip emits blue light. The colored light excites the red conversion material to emit red light, thus forming three primary colors of light to achieve full-color display.

In some embodiments of the present invention, the light-emitting chip is a blue LED chip for emitting blue light. Each light-emitting unit serves as a sub-pixel. In order to achieve full-color display, the light-emitting unit is divided into red light-emitting unit, green light-emitting unit and blue light-emitting unit. The red light-emitting unit, the green light-emitting unit and the blue light-emitting unit are repeatedly arranged in a set order. The red light-emitting unit acts as a red sub-pixel, the green light-emitting unit acts as a green sub-pixel, and the blue light-emitting unit acts as a blue sub-pixel. The adjacent one A red light-emitting unit, a green light-emitting unit and a blue light-emitting unit constitute a pixel unit. The nanopores of the light-transmitting matrix layer of the red light-emitting unit are filled with red conversion material, which is used to emit red light under the excitation of the blue light emitted by the light-emitting chip; the nanopores of the light-transmitting matrix layer of the green light-emitting unit are filled with green Conversion material, the green conversion material is used to emit green light under the excitation of the blue light emitted from the light-emitting chip; the nanopores of the light-transmitting matrix layer of the blue light-emitting unit may not be filled or filled with transparent media, so that the blue light-emitting unit Blue light is emitted, thereby forming three primary colors of light, achieving full-color display.

In some embodiments of the present invention, the light-emitting chip includes: an n-type doped layer, a light-emitting layer, a p-type doped layer, a dielectric layer and an electrode.

In some embodiments of the present invention, the n-type doped layer is an n-type doped GaN layer, the p-type doped layer is a p-type doped GaN layer, and the light-transmitting matrix layer uses an n-type heavily doped GaN layer. Therefore, it can be used A lower-cost electrochemical etching method forms nanopores in the n-type heavily doped GaN layer.

In some embodiments of the present invention, a first filter layer is provided between the n-type heavily doped GaN layer and the n-type doped GaN layer. On the one hand, the first filter layer plays the role of electrical isolation between the n-type heavily doped GaN layer and the n-type doped GaN layer. On the other hand, it is also used to transmit blue light and reflect red light and green light.

In some embodiments of the present invention, when only the red light-emitting unit includes a light-emitting chip and a light-transmitting matrix layer, a first filter layer is provided in the red light-emitting unit. The first filter layer can transmit the blue light emitted by the light-emitting chip, and at the same time, the red light-emitting unit can transmit the blue light emitted by the light-emitting chip. The red light stimulated by the conversion material is reflected toward the side away from the driving substrate, thereby improving the light extraction efficiency.

In some embodiments of the present invention, when each light-emitting unit includes a light-emitting chip and a light-transmitting matrix layer, each light-emitting unit is provided with a first filter layer, and the first filter layer can transmit the blue light emitted by the light-emitting chip. At the same time, the red light and green light stimulated and emitted by the red light-emitting unit and the green light-emitting unit can be reflected to the side away from the driving substrate, thereby improving the light extraction efficiency.

In some embodiments of the present invention, after forming the epitaxial layer of the light-emitting chip, a plurality of light-emitting units arranged in an array are formed by etching, and the side walls of the light-emitting units have a certain tilt angle.

In some embodiments of the present invention, the display device further includes a passivation layer. The passivation layer is located on at least part of the surface of the light-emitting unit facing away from the driving substrate and the side wall of each light-emitting unit. After the epitaxial layer is etched to form a light-emitting unit, defects will occur in the sidewalls. Therefore, forming a passivation layer on the surface of the light-emitting unit can reduce sidewall defects, reduce non-radiative recombination, and increase luminous efficiency.

In some embodiments of the present invention, the display device further includes a second filter layer. The second filter layer is located on the surface and side wall of each red light-emitting unit or each red light-emitting unit and each green light-emitting unit facing away from the driving substrate. on the chemical layer. The second filter layer is used to transmit red light and green light and reflect blue light. Since the conversion efficiency of the color conversion material for the blue light emitted by the light-emitting chip is not 100%, the direct emission of unused blue light will cause a color shift problem between the red light-emitting unit and the green light-emitting unit. Therefore, providing a second filter layer on the light exit side of the red light-emitting unit and the green light-emitting unit can reflect the unused blue light back into the light-emitting unit to excite the color conversion material again, thereby improving the light extraction efficiency of the red and green light-emitting units. The second filter layer located in the isolation groove also acts as an isolation layer. The second filter layer reflects blue light on the one hand to prevent blue light from emitting to adjacent light-emitting units and causing crosstalk, and on the other hand it can reduce blue light. Reduce color light loss and improve light emission efficiency. The isolation property achieved by the second filter layer through reflection can also avoid the problem of device performance degradation caused by light absorption and heat generation.

In some embodiments of the present invention, the blue light emitted from the light-emitting layer in the light-emitting chip is emitted in various directions, and a part of the blue light is incident into the nanopore, excites the color conversion material, and is converted into red light or green light. The converted red light or green light is emitted in various directions. Part of the red light or green light is emitted outward through the second filter layer, and the other part of the red light or green light emitted toward the side of the light-emitting chip is filtered by the first filter layer. After reflection, it emits outward. The blue light that has not been completely converted cannot pass through the second filter layer, and is reflected back into the light-emitting unit by the second filter layer. After passing through the first filter layer and the epitaxial layer of the light-emitting chip, it is reflected by the electrode, stimulating color conversion again. The material is converted into red light or green light and emitted outward until it is completely converted. The blue light emitted from the side of the light-emitting chip is reflected by the second filter layer at the side wall and then returned to the light-emitting unit. It is converted into red light or green light by exciting the color conversion material and then emitted outward. As a result, only the converted red light or green light can be emitted outwardly from the light-emitting unit, which improves the conversion efficiency of blue light, improves the emission efficiency of red light or green light, and reduces light loss.

In some embodiments of the present invention, the blue light-emitting unit is arranged adjacent to the red light-emitting unit and the green light-emitting unit, so the side wall of the blue light-emitting unit is adjacent to the second filter layer on the periphery of the red light-emitting unit or the green light-emitting unit. In the blue light-emitting unit, the nanopores are not filled or filled with transparent media. The blue light emitted from the light-emitting chip is emitted in all directions. The blue light emitted from the front is emitted directly outward, and the blue light emitted from the side is emitted from the side wall. The second filter layer changes direction after reflection, and finally emerges from the front of the blue light-emitting unit after multiple reflections. This can enhance the light extraction efficiency of the front of the blue light-emitting unit and reduce crosstalk.

In some embodiments of the present invention, both the first filter layer and the second filter layer may use Bragg reflective layers.

In some embodiments of the present invention, the display device further includes: a bonding layer and a packaging substrate. The bonding layer is located on a surface of the second filter layer facing away from the driving substrate. The packaging substrate is located on a surface of the bonding layer facing away from the driving substrate.

Description of the drawings

In order to explain the technical solutions of the embodiments of the present invention more clearly, the drawings required to be used in the embodiments of the present invention will be briefly introduced below. Obviously, the drawings introduced below are only some embodiments of the present invention. Those of ordinary skill in the art can also obtain other drawings based on these drawings without exerting creative efforts.

Figure 1 is a schematic cross-sectional structural diagram of a display device provided by an embodiment of the present invention;

Figure 2 is a schematic cross-sectional structural diagram of a pixel unit provided by an embodiment of the present invention;

Figure 3 is a second schematic cross-sectional structural diagram of a pixel unit provided by an embodiment of the present invention;

Figure 4 is a schematic cross-sectional structural diagram of a red (green) light-emitting unit provided by an embodiment of the present invention;

FIG. 5 is a schematic cross-sectional structural diagram of a blue light-emitting unit provided by an embodiment of the present invention.

Among them, 1-driving substrate, 2-light-emitting unit, 2r-red light-emitting unit, 2b-blue light-emitting unit, 2g-green light-emitting unit, 3-passivation layer, 4-second filter layer, 5-bonding layer , 6-packaging substrate, 21-light-emitting chip, 22-light-transmitting matrix layer, h-nanohole, 23-first filter layer, 211-n-type doping layer, 212-light-emitting layer, 213-p-type doping Layer, 214-dielectric layer, 215-electrode, c-substrate.

Detailed ways

In order to make the above objects, features and advantages of the present invention more obvious and understandable, the present invention will be further described below with reference to the accompanying drawings and embodiments. Example embodiments may, however, be embodied in various forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concepts of the example embodiments. To those skilled in the art. The same reference numerals in the drawings represent the same or similar structures, and thus their repeated description will be omitted. The words expressing position and direction described in the present invention are all explained by taking the accompanying drawings as examples, but they can be changed as needed, and all changes are included in the protection scope of the present invention. The drawings of the present invention are only used to illustrate relative positional relationships and do not represent true proportions.

Self-luminous display devices have the advantages of not requiring a backlight module, simple device structure, and lower dark field brightness, and have become the focus of research in the display field.

Light Emitting Diode (LED) display technology refers to the use of light-emitting diodes as light-emitting devices for direct image display. Micro LED (Micro Light Emitting Diode, MicroLED for short) specifically refers to miniaturized LED chips. Generally, the size of Micro LED is on the order of microns. For example, the size of Micro LED is less than 100 μm. When the size of Micro LED chips is reduced to the pixel level, Micro LEDs can be directly used as light-emitting units for image display.

Current LED display devices usually use three primary color light-emitting chips for full-color display. Among them, red LED chips are based on AlGaInP. Compared with GaN-based green LED chips and blue LED chips, AlGaInP-based red LEDs have low efficiency, brittle texture, and poor yield, especially when the size is reduced to the micron level. , and the efficiency dropped sharply. GaN-based green LED chips and GaN-based blue LED chips have higher efficiency and yield, and lower manufacturing costs. Therefore, red light can be produced by combining blue LED chips with color conversion materials, which can reduce costs and achieve higher luminous efficiency.

The commonly used method at present is to coat the color conversion material on the surface of the blue LED chip. Since the shape of the color conversion material is difficult to control, it is difficult to convert all the blue light, and there is a color shift phenomenon. If a filter is used to filter light, the light emitted from the blue LED chip, which is one of the three primary colors of light, will be suppressed, resulting in reduced efficiency.

In addition, the refractive index of the epitaxial material of the LED is greatly different from that of air and substrate materials. The light emitted from the light-emitting layer of the LED chip is totally reflected at the interface between the high-refractive index material and the low-refractive index material, causing the LED chip to emit light. The emitted light from the epitaxial layer propagates in the form of a waveguide within the epitaxial layer film and is eventually reabsorbed by the epitaxial layer, thus limiting the light extraction efficiency of the LED chip.

In order to overcome the above problems, an embodiment of the present invention provides a display device. FIG. 1 is a schematic cross-sectional structural diagram of the display device provided by an embodiment of the present invention.

As shown in FIG. 1 , a display device provided by an embodiment of the present invention includes: a driving substrate 1 and a light-emitting unit 2 .

The driving substrate 1 is located at the bottom of the display device. Generally, its size is adapted to the overall size of the display device. The size of the driving substrate 1 is slightly smaller than the size of the display device.

In some embodiments, the display device may also include multiple drive substrates 1 , and the drive substrates 1 jointly provide drive signals through splicing. In order to avoid optical problems caused by the splicing of drive substrates 1, the splicing seams between adjacent drive substrates 1 should be kept as small as possible, and even seamless splicing can be achieved.

The shape of the driving substrate 1 is the same as the overall shape of the display device, and usually can be set in a rectangular or square shape. When the display device is a special-shaped display device, the shape of the driving substrate can be adaptively set to other shapes, which is not limited here.

The driving substrate 1 is used to provide driving signals to the light emitting unit 2 . Typically, a circuit board or array substrate can be used.

The circuit board can be a Printed Circuit Board (PCB for short), and when applied to a flexible display, a Flexible Printed Circuit (FPC for short) can be used, which is not limited here.

The array substrate can be manufactured using currently mature thin film technology. For its specific structure, please refer to the array substrate of an LCD or OLED display device in the prior art, which will not be described in detail here.

The light-emitting unit 2 is located on the driving substrate 1 and is electrically connected to the driving substrate 1. The driving substrate 1 is used to provide a driving signal to the light-emitting unit 2, thereby controlling the brightness of the light-emitting unit 2 to achieve image display.

In the embodiment of the present invention, as shown in FIG. 1 , each light-emitting unit 2 includes a light-emitting chip 21 , and at least some of the light-emitting units 2 also include a light-transmitting matrix layer 22 .

The light-emitting chip 21 is located on a side close to the driving substrate 1 and is electrically connected to the driving substrate 1; the driving substrate 1 can provide driving signals to each light-emitting chip 21 respectively, thereby controlling the luminous brightness of each light-emitting chip 21 respectively.

The light-emitting chip 21 may be an LED chip, a Mini LED chip or a Micro LED chip. Among them, the size of Mini LED chips and Micro LED chips can reach sub-millimeter or micron levels, and the size of Mini LED chips is larger than the size of Micro LED chips. When applied to different application scenarios and have different requirements for pixel levels, different sizes of light-emitting chips can be used according to the implementation situation, which is not limited here.

At least part of the light-emitting unit also includes a light-transmissive matrix layer 22 . The light-transmitting matrix layer 22 is located on the side of the light-emitting chip 21 away from the driving substrate 1; the light-transmitting matrix layer 22 includes a plurality of nanoholes h. The light-transmitting matrix layer 22 can be made of light-transmitting material, and the light-transmitting matrix layer 22 is located on the light-emitting side of the light-emitting unit 2 . In the embodiment of the present invention, a light-transmitting matrix layer 22 is provided on the light-emitting side of the light-emitting chip 21 in order to form nanoholes h in the light-transmitting matrix layer 22 . Different materials can be selected as the light-transmitting matrix layer 22 according to the manufacturing process of the nanohole h.

In the embodiment of the present invention, in order to improve the luminous efficiency of some light-emitting units and use it for full-color display, the nanoholes h of the light-transmitting matrix layer 22 are filled with color conversion materials, so that the color conversion materials can be used in the emitted light of the light-emitting chip 21 When excited, other colors of light are emitted.

By replacing the light-emitting units with low luminous efficiency in the display device with a light-transmitting matrix layer on the light-emitting side of the light-emitting chip, and filling the nanopores of the light-transmitting matrix layer with color conversion materials, the luminous efficiency of each light-emitting unit in the display device can be improved. Luminous efficiency.

Setting the light-transmitting matrix layer 22 separately for forming the nanohole h can avoid directly forming the nanohole in the light-emitting chip from affecting the light extraction efficiency of the light-emitting chip. After the light emitted from the light-emitting chip 21 is incident on the light-transmitting matrix layer, the light can be emitted in various directions through the nanopores due to the distribution of nano-h, thereby destroying the total reflection condition when the light is emitted outward and improving the light extraction efficiency.

In specific implementation, the nanopore h can be produced by electrochemical etching, inductively coupled plasma etching (Inductively Coupled Plasma Etch, ICPE for short), electron beam exposure (Electron BeamLithography, EBL) etching, etc., nanopore h It can be regular or irregular, uniformly distributed or regionally distributed. The diameter of nanopore h can be nanoscale, between 1nm and 1000nm, or even larger. The depth of nanopore h can be 0.1 Between μm and 10μm, there is no limit here.

The color conversion materials filled in the nanopores can be fluorescent materials or quantum dot materials. Among them, quantum dot materials can achieve a higher color gamut. Specifically, they can be produced through inkjet printing, atomization spraying, spin coating, photolithography and other methods, and then through vacuum, vibration, ultrasound, cavitation, pressure, electrostatic adsorption and other technologies. Delivering quantum dot materials into nanopores.

Quantum dot materials can be perovskite quantum dots, CdSe colloidal quantum dots, ZnS, ZnSe, CdSe, InP, CdS, PbS, InAs, GaP, GaAs, etc., which are not limited here.

FIG. 2 is a schematic cross-sectional structural diagram of a pixel unit provided by an embodiment of the present invention.

In some embodiments, the colors of the light emitted by the light-emitting chips included in the light-emitting unit may be different. Each light-emitting unit serves as a sub-pixel. In order to achieve full-color display, as shown in Figure 2, the light-emitting unit is divided into a red light-emitting unit 2r, Green light emitting unit 2g and blue light emitting unit 2b. The red light-emitting unit 2r, the green light-emitting unit 2g and the blue light-emitting unit 2b are usually arranged repeatedly in a set order. The red light-emitting unit 2r serves as a red sub-pixel, the green light-emitting unit 2g serves as a green sub-pixel, and the blue light-emitting unit 2b serves as a blue sub-pixel. As a sub-pixel, a red light-emitting unit 2r, a green light-emitting unit 2g and a blue light-emitting unit 2b are adjacent to form a pixel unit.

The green light-emitting unit 2g and the blue light-emitting unit 2b only include the light-emitting chip 21 and the substrate c. The red light-emitting unit 2r includes a light-emitting chip 21 and a light-transmitting matrix layer 22 located on the side of the light-emitting chip away from the driving substrate 1, and the nanopores h of the light-transmitting matrix layer 22 are filled with red conversion materials.

Among them, the light-emitting chip included in the green light-emitting unit 2g is a green light-emitting chip used to emit green light, the light-emitting chip included in the blue light-emitting unit 2b is a blue light-emitting chip used to emit blue light, and the red light-emitting unit 2r includes a light-emitting chip. It is a blue light-emitting chip used to emit blue light. As a result, the green light-emitting chip emits green light, the blue light-emitting chip emits blue light, and the blue light emitted by the blue light-emitting chip excites the red conversion material to emit red light, thus forming three primary colors of light to achieve full-color display.

In specific implementation, the green light-emitting chip can use a green LED chip, the blue light-emitting chip can use a blue LED chip, and the substrate c on the surface of the green LED chip and the blue LED chip can be used to make the blue LED chip and the green LED chip. The substrate, for example, the substrate c can be a sapphire substrate. Only the red light-emitting unit 2r is configured in a manner that the blue LED chip excites the red conversion material, so that the light-emitting units of each color have higher luminous efficiency.

The red conversion material can be a red quantum dot material. The luminescence wavelength of the red quantum dot is 600nm~700nm, and the luminescence wavelength of the blue LED chip is 400nm~480nm. Red quantum dots are filled in the nanopores, and the stimulated emission of red light is emitted in all directions, thus destroying the total reflection condition for light to emit from the device, thereby improving light extraction efficiency.

FIG. 3 is a second schematic cross-sectional structural diagram of a pixel unit provided by an embodiment of the present invention.

In some embodiments, the color of the emitted light from the light-emitting chips 21 of each light-emitting unit can be the same, and each light-emitting unit 2 serves as a sub-pixel. In order to achieve full-color display, as shown in Figure 3, the light-emitting units are divided into red light-emitting units. 2r, green light-emitting unit 2g and blue light-emitting unit 2b. The red light-emitting unit 2r, the green light-emitting unit 2g and the blue light-emitting unit 2b are usually arranged repeatedly in a set order. The red light-emitting unit 2r serves as a red sub-pixel, the green light-emitting unit 2g serves as a green sub-pixel, and the blue light-emitting unit 2b serves as a blue sub-pixel. As a sub-pixel, a red light-emitting unit 2r, a green light-emitting unit 2g and a blue light-emitting unit 2b are adjacent to form a pixel unit.

The red light-emitting unit 2r, the green light-emitting unit 2g and the blue light-emitting unit 2b each include a light-emitting chip 21 and a light-transmitting matrix layer 22 located on the side of the light-emitting chip away from the driving substrate 1.

Among them, the light-emitting chips included in the red light-emitting unit 2r, the green light-emitting unit 2g and the blue light-emitting unit 2b are all blue light-emitting chips used to emit blue light. For example, a blue LED chip can be used. The nanopores h of the light-transmitting matrix layer of the red light-emitting unit 2r are filled with red conversion material, so that the red conversion material emits red light under the stimulation of the blue light emitted by the light-emitting chip 21; the nanometer holes h of the light-transmitting matrix layer of the green light-emitting unit 2g are filled with red conversion material. The green conversion material is filled in the hole h, so that the green conversion material emits green light under the excitation of the blue light emitted by the light-emitting chip 21 . The nanohole h of the light-transmitting matrix layer of the blue light-emitting unit 2b may not be filled or filled with a transparent medium, so that the blue light-emitting unit 2b emits blue light, thereby forming three primary color lights and achieving full-color display.

In the embodiment of the present invention, the red conversion material may be a red quantum dot material, and the green conversion material may be a green quantum dot. The luminescent wavelength of red quantum dots is 600nm~700nm, the luminescent wavelength of green quantum dots is 490nm~580nm, and the luminescent wavelength of blue LED chips is 400nm~480nm. Red quantum dots and green quantum dots are filled in the nanopore, and the stimulated emission of red light and green light is emitted in all directions; while the blue light emitted by the blue LED chip in the blue light-emitting unit is emitted in all directions after passing through the nanopore. Both can destroy the total reflection condition for light emitted from the device, thereby improving light extraction efficiency.

It is worth noting that the display device provided by the embodiment of the present invention can adopt at least two structures.

In one structure, as shown in Figure 2, the green light-emitting unit uses a green LED chip; the blue light-emitting unit uses a blue LED chip; only the red light-emitting unit uses a blue LED chip superimposed on a light-transmitting matrix layer, and on the light-transmitting matrix layer A structure with nanopores filled with red conversion material. This is because red LED chips have lower luminous efficiency than green LED chips and blue LED chips. Adopting the above structure can improve the luminous efficiency of the red light-emitting unit. At this time, the green light-emitting unit, the blue light-emitting unit and the red light-emitting unit need to be manufactured separately and then transferred to the driving substrate respectively.

In another structure, as shown in Figure 3, the red light-emitting unit, the green light-emitting unit and the blue light-emitting unit all use blue LED chips superimposed on the light-transmitting matrix layer, and between the light-transmitting matrix layers of the red light-emitting unit and the green light-emitting unit The nanopores are filled with color-converting materials. Since the light-emitting units of each color use the same light-emitting chip, the light-emitting units can be manufactured together, cut according to the pixel unit or multiple pixel units, and then transferred to the driving substrate. At this time, the number of huge transfers can be reduced and the transfer efficiency can be improved. And it is no longer limited by the huge amount of transfer, and the distance between the light-emitting units in the pixel unit can be further reduced to install more pixel units in a limited space and improve the display resolution.

When a single light-emitting unit is used as a light-emitting device, that is, when the structure shown in Figure 2 is used, the lateral size of the light-emitting device is about 4 μm to 200 μm; when it consists of a red light-emitting unit 2r, a green light-emitting unit 2g and a blue light-emitting unit When the pixel unit composed of 2b is used as a light-emitting device, that is, when the structure shown in Figure 3 is adopted, the lateral size of the light-emitting device is approximately 10 μm to 600 μm.

Figure 4 is a schematic cross-sectional structural diagram of a red (green) light-emitting unit provided by an embodiment of the present invention.

As shown in FIGS. 2 to 4 , no matter which display panel structure is adopted, the light-emitting chip 21 includes: an n-type doped layer 211 , a light-emitting layer 212 , a p-type doped layer 213 , a dielectric layer 214 and an electrode 215 .

The n-type doped layer 211, the light-emitting layer 212 and the p-type doped layer 213 are stacked and grown on a suitable substrate using LED epitaxial technology. Among them, the n-type doping layer 211 and the p-type doping layer 213 can be obtained by using the same material and performing n-type doping and p-type doping respectively. The thickness of the n-type doped layer 211 is about 2 μm to 4 μm, and the thickness of the p-type doped layer 213 is about 100 nm to 1000 nm. The light-emitting layer 212 may use multiple quantum wells, which is beneficial to improving the light-emitting efficiency. The thickness of the light-emitting layer 212 is approximately 100 nm to 500 nm.

The light-emitting layer 212 and the p-type doped layer 213 expose part of the n-type doped layer 211 for forming electrodes. Before forming the electrodes, a dielectric layer 214 is formed on the exposed surfaces of the n-type doped layer 211 and the p-type doped layer 213. The dielectric layer 214 is used to protect the non-electrode area from being affected by the external environment and to avoid short circuits between electrodes. The dielectric layer 214 can be made of one or more materials selected from SiO ₂ , AlN, Al ₂ O ₃ , and AlON, by atomic layer deposition or plasma chemical vapor deposition. The thickness of the dielectric layer 214 is approximately 100 nm to 1000 nm.

The dielectric layer 214 includes two through holes that expose part of the n-type doped layer 211 and part of the p-type doped layer 213 respectively; the two electrodes 215 are connected to the exposed n-type doped layer 211 and p-type layer 211 through the two through holes respectively. type doped layer 213 contacts. The electrode connected to the n-type doped layer 211 is the n electrode, and the electrode connected to the p-type doped layer 213 is the p electrode. The n electrode can be made of Ti/Al/Ni/Au metal, and the p electrode can be made of Ni/Au metal. To make the electrode The materials may include, but are not limited to, Cr, Ti, Ni, Au, Sn, Sn, Al, Au, Pt and other metals or combinations.

When using the structure shown in Figure 2, the light-emitting chips in the red light-emitting unit 2r and the light-emitting chips in the blue light-emitting unit use blue LED chips, and the light-emitting chips in the green light-emitting unit use green LED chips; when using the structure shown in Figure 3 In the structure shown, the light-emitting chips 21 in all light-emitting units use blue LED chips. In the embodiment of the present invention, both the blue LED chip and the green LED chip are based on GaN. Taking the blue LED chip as an example, the n-type doped layer 211 can be an n-type doped GaN layer, and the doping concentration range is about 2×10 ¹⁷ /cm ³ ~ 8×10 ¹⁸ /cm ³ ; the p-type doped layer 213 It can be a p-type doped GaN layer, and the doping concentration range is about 1×10 ¹⁹ /cm ³ ~ 1×10 ²⁰ /cm ³ . The light-emitting layer 212, that is, the multi-quantum well layer is grown alternately from an InGaN quantum well layer and a GaN barrier layer. Electrons and holes radiate and recombine in the InGaN/GaN multi-quantum well to emit photons, thereby controlling the density of the well layer and the barrier layer. The thickness, composition and period can control the luminescence wavelength. In the embodiment of the present invention, the multi-quantum well layer emits blue light, and the luminescence wavelength is 400nm~480nm.

Furthermore, consider the production cost, the material system used in the light-emitting chip, and whether the material is convenient for forming nanopores. In the embodiment of the present invention, the light-transmitting matrix layer 22 can be an n-type heavily doped GaN layer, so that a lower-cost electrochemical etching method can be used to form nanoholes h in the n-type heavily doped GaN layer.

Specifically, the doping concentration range of the n-type heavily doped GaN layer is approximately 2×10 ¹⁸ /cm ³ to 1×10 ²⁰ /cm ³ . The thickness of the n-type heavily doped GaN layer is about 0.1μm~10μm.

The GaN in the embodiment of the present invention can be non-polar GaN, semi-polar GaN or c-plane GaN, which is not limited here.

Using GaN for n-type doping is beneficial to the formation of nanoholes h, but is not conducive to ohmic contact and light emission; and the doping concentration of the n-type doped GaN layer in the light-emitting chip cannot be too high, otherwise n-type carriers and p Unbalanced carrier transport capacity will cause the luminous efficiency of the light-emitting chip to decrease.

In view of this, in the embodiment of the present invention, as shown in Figures 2 to 4, a first filter layer 23 is provided between the n-type heavily doped GaN layer (22) and the n-type doped GaN layer (211) separated. On the one hand, the first filter layer 23 serves as an electrical isolation between the n-type heavily doped GaN layer (22) and the n-type doped GaN layer (211). On the other hand, it is also used to transmit blue light and reflect red light. light and green light.

When the structure shown in FIG. 2 is adopted, only the first filter layer 23 is provided in the red light-emitting unit 2r. The first filter layer 23 can transmit the blue light emitted by the light-emitting chip 21 and at the same time stimulate the emission of the red conversion material. The red light is reflected toward the side away from the driving substrate to improve the light extraction efficiency.

When the structure shown in FIG. 3 is adopted, a first filter layer 23 is provided in each light-emitting unit. The first filter layer 23 can transmit the blue light emitted by the light-emitting chip 21, and at the same time, can reflect the red light and green light stimulated and emitted by the red light-emitting unit 2r and the green light-emitting unit 2g to the side away from the driving substrate, thereby improving light extraction. efficiency.

When using the structure shown in Figure 2, both the green light-emitting unit 2g and the blue light-emitting unit 2b use light-emitting chips to directly emit light, and their manufacturing methods are different from the red light-emitting unit 2r. As shown in Figure 2, for the green light-emitting unit 2g and the blue light-emitting unit 2b, the light-emitting unit also includes a substrate c located on the side of the light-emitting chip 21 away from the driving substrate. The substrate c can be used to make blue LED chips and green light-emitting units. The substrate for the light LED chip, for example, the substrate c can be a sapphire substrate.

When the structure shown in Figure 3 is adopted, each light-emitting unit is manufactured together. The red light-emitting units 2r in Figure 2 are usually made in plural at one time and then cut into multiple red light-emitting units. Therefore, during the manufacturing process, after forming the epitaxial layer of the light-emitting chip, a plurality of light-emitting units 2 arranged in an array are formed by etching, and isolation grooves are etched between adjacent light-emitting units. As shown in Figure 3, the width of the isolation groove U close to the driving substrate 1 is smaller than the width of the isolation groove U away from the driving substrate 1, so that the side wall of the light-emitting unit 2 has a certain inclination angle, and the isolation groove U is wide at the top and wide at the bottom. Narrow structure.

Filling the isolation trench U with insulating material can isolate the light-emitting units 2 from each other. In the embodiment of the present invention, as shown in FIG. 3 , the display device further includes a passivation layer 3 . The passivation layer 3 is not only formed on the light-emitting side surface of the light-emitting unit 2, but also filled in the isolation trench U between the light-emitting units to cover the side walls of the light-emitting unit 2.

Specifically, the passivation layer 3 is located on the surface of each light-emitting unit facing away from the driving substrate 1 and on the side wall of each light-emitting unit. After the epitaxial layer is etched to form a light-emitting unit, defects will occur in the sidewalls. Therefore, forming a passivation layer 3 on the surface of the light-emitting unit 2 can reduce sidewall defects, reduce non-radiative recombination, and increase luminous efficiency.

For the red light-emitting unit in the structure of Figure 2, and the red light-emitting unit and green light-emitting unit in the structure of Figure 3, the passivation layer 3 can also protect the quantum dots from the impact of subsequent processes and the sidewalls of the light-emitting unit.

In specific implementation, the passivation layer 3 can be made of one or more materials among SiO ₂ , AlN, Al ₂ O ₃ , and AlON through atomic layer deposition or plasma chemical vapor deposition. The passivation layer 3 surrounds the light-emitting side surface and side walls of the light-emitting unit. The part of the passivation layer 3 that covers the light-emitting side surface of the light-emitting unit is a plane, and the part that covers the side wall of the light-emitting unit is a slope. The size of the passivation layer on the slope part is equivalent to the thickness of the light-emitting unit, which is about 4 μm to 20 μm, and the thickness of the passivation layer 3 is about 1 nm to 1 μm. Since the side wall of the light-emitting unit is a bevel, it is beneficial to form a passivation layer on the side wall. The angle between the planar part of the passivation layer and the bevel part is about 95° to 160°.

As shown in FIGS. 2 and 3 , the display device is also provided with a second filter layer 4 on the surface of some light-emitting units. Specifically, when the structure shown in FIG. 2 is adopted, the second filter layer 4 is located on the passivation layer 3 on the surface and side wall of the red light-emitting unit 2r facing away from the driving substrate. When the structure shown in FIG. 3 is adopted, the second filter layer 4 is located on the passivation layer 3 on the surface and side wall of each red light-emitting unit 2r and each green light-emitting unit 2g away from the driving substrate.

The shape of the passivation layer 3 on the surface of the light-emitting unit 2 is the same as that of the light-emitting unit 2. Therefore, the second filter layer 4 formed on the surface of the passivation layer 3 has a planar part and a slope part like the passivation layer 3. Wherein, the planar part of the second filter layer 4 corresponds to the light-emitting side surface of the light-emitting unit, and the slope part corresponds to the side wall of the light-emitting unit. The slope of the passivation layer 3 is conducive to forming the second filter layer 4 thereon, and the angle between the planar part and the slope part of the second filter layer 4 is about 95° to 160°.

In the embodiment of the present invention, the second filter layer 4 is used to transmit red light and green light and reflect blue light. Since the conversion efficiency of the color conversion material for the blue light emitted by the light-emitting chip is not 100%, the direct emission of unused blue light will cause a color shift problem between the red light-emitting unit and the green light-emitting unit. Therefore, arranging the second filter layer 4 on the light exit side of the red light-emitting unit and the green light-emitting unit can reflect the unused blue light back into the light-emitting unit to excite the color conversion material again, thereby improving the light extraction efficiency of the red light-emitting unit and the green light-emitting unit. .

In the embodiment of the present invention, by arranging the first filter layer 23 and the second filter layer 4 to form a reflective cavity for light of different colors, the conversion efficiency of blue light can be improved and the light loss can be reduced.

Figure 4 shows the light path of the red light-emitting unit or the green light-emitting unit, wherein the dotted line represents the light path of the blue light, and the solid line represents the light path of the red light or green light stimulated and emitted by the color conversion layer in the red light-emitting unit or the green light-emitting unit. .

As shown in FIG. 4 , the blue light emitted from the light-emitting layer 212 in the light-emitting chip 21 is emitted in various directions, and a part of the blue light is incident into the nanohole h, excites the color conversion material, and is converted into red light or green light. The converted red light or green light is emitted in various directions, and part of the red light or green light is emitted outward through the second filter layer 4 , and the other part of the red light or green light emitted toward the light-emitting chip 21 is absorbed by the first The filter layer 23 reflects and then emits outward. The blue light that has not been completely converted cannot pass through the second filter layer 4 and is reflected back into the light-emitting unit by the second filter layer 4. After passing through the first filter layer 23 and the epitaxial layer of the light-emitting chip, it is reflected by the electrode and is reflected again by the electrode. The excited color conversion material is converted into red light or green light and emitted outward until complete conversion. The blue light emitted from the side of the light-emitting chip 21 is reflected by the second filter layer 4 at the side wall and then returns to the light-emitting unit. It is converted into red light or green light by exciting the color conversion material and then emitted outward. As a result, only the converted red light or green light can be emitted outwardly from the light-emitting unit, which improves the conversion efficiency of blue light, improves the emission efficiency of red light or green light, and reduces light loss.

Figure 5 shows the optical path of the blue light-emitting unit, in which the dotted line represents the optical path of the blue light.

As shown in FIG. 5 , the blue light-emitting unit is arranged adjacent to the red light-emitting unit and the green light-emitting unit. Therefore, the side wall of the blue light-emitting unit is adjacent to the second filter layer 4 on the periphery of the red light-emitting unit or the green light-emitting unit. In the blue light-emitting unit, the nanopores are not filled or filled with transparent media, and the blue light emitted from the light-emitting chip 21 is emitted in all directions. The blue light emitted from the front is emitted directly outward, and the blue light emitted from the side is emitted from the side wall. The second filter layer 4 changes direction after reflection, and finally emerges from the front of the blue light-emitting unit after multiple reflections. This can enhance the light extraction efficiency of the front of the blue light-emitting unit and reduce crosstalk.

The second filter layer 4 located in the isolation groove U also acts as an isolation layer. The function of the second filter layer 4 in reflecting blue light can prevent blue light from emitting to adjacent light-emitting units and causing crosstalk on the one hand. It can reduce blue light loss and improve light emission efficiency. The isolation property achieved by reflection of the second filter layer 4 can also avoid the problem of device performance degradation caused by light absorption and heat generation.

In specific implementation, both the first filter layer 23 and the second filter layer 4 can use Bragg reflective layers. The Bragg reflective layer is generally a periodic thin film composed of at least two high refractive index materials and low refractive index materials alternately arranged. By adjusting the refractive index and thickness of the film layer material, the first filter layer 23 and the second filter layer 4 can be The reflectivity reaches more than 95%, even close to 100%.

For the first filter layer 23, the reflectivity of the first filter layer 23 can be lower in the blue light band (420nm~480nm) and lower in the green light band (500nm~580nm) and the red light band (600nm~700nm) through design. ) has a high reflectivity, thereby transmitting blue light and reflecting red and green light.

For the second filter layer 4, the design can make the second filter layer 4 have a higher reflectivity in the blue light band (420nm~480nm), while the green light band (500nm~580nm) and red light band (600nm~700nm) ) has a low reflectivity, thereby reflecting blue light and transmitting red and green light.

In specific implementation, two materials with different refractive indexes, SiO ₂ and TiO ₂ , can be repeatedly stacked to form a Bragg reflection layer. The Bragg reflective layer may have a single stack structure, a multi-stack structure, or a gradient structure, which is not limited here. In addition, the material of the Bragg reflective layer may be one or a combination of silicon oxide, titanium oxide, hafnium oxide, magnesium fluoride, yttrium oxide, zinc sulfide, zirconium oxide and silicon nitride.

In the embodiment of the present invention, the first filter layer 23 has a planar structure and a thickness of approximately 200 nm to 1000 nm. The second filter layer 4 includes a planar part and a bevel part. The thickness of the planar part and the bevel part is equivalent, about 200 nm to 3 μm. The angle between the flat part and the inclined part is about 95° to 160°.

As shown in FIGS. 2 and 3 , the display device also includes: a bonding layer 5 and a packaging substrate 6 . The bonding layer 5 is located on the surface of the second filter layer 4 facing away from the driving substrate 1 . The packaging substrate 6 is located on the surface of the bonding layer 5 facing away from the driving substrate 1 .

The bonding layer 5 transmits all three primary colors of red, green, and blue light, and is used to bond or bond the light-emitting unit to the packaging substrate 6 . The bonding layer 5 can be made of silicon dioxide, alumina, epoxy resin, epoxy plastic sealing compound, silica gel or organic silicon plastic, with a thickness of about 100 nm to 1000 nm.

The packaging substrate 6 is transparent to all three primary colors of red, green, and blue, and may be partially transparent or fully transparent. The packaging substrate 6 is located on the outermost side of the device and plays a role in protecting and supporting the functional area of the device. The packaging substrate 6 may have one or more qualities such as, but not limited to, being scratch-resistant, scratch-resistant, shatter-proof, heat-resistant, flexible, electrically conductive and/or electrically resistant, providing polarized light filtering and/or coloring. The packaging substrate 6 can be made of sapphire, quartz glass, glass and other materials, which are not limited here.

Although the preferred embodiments of the present invention have been described, those skilled in the art will be able to make additional changes and modifications to these embodiments once the basic inventive concepts are apparent. Therefore, it is intended that the appended claims be construed to include the preferred embodiments and all changes and modifications that fall within the scope of the invention.

Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the invention. In this way, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims (10)

1. A display device, comprising:

a driving substrate for providing a driving signal;

the light-emitting units are positioned on the driving substrate and are electrically connected with the driving substrate;

each light-emitting unit comprises a light-emitting chip; the light-emitting chip is positioned at one side close to the driving substrate and is electrically connected with the driving substrate;

at least part of the light emitting unit further comprises a light-transmitting matrix layer; the light-transmitting matrix layer is positioned on one side of the light-emitting chip, which is away from the driving substrate; the light-transmitting substrate layer comprises a plurality of nanopores; and the nanopores of the light-transmitting matrix layer of part of the light-emitting units are filled with color conversion materials, and the color conversion materials are used for emitting light of other colors under the excitation of the emitted light of the light-emitting chip.

2. The display device according to claim 1, wherein the light emitting units are divided into a red light emitting unit, a green light emitting unit, and a blue light emitting unit;

the blue light emitting unit comprises a blue light emitting chip for emitting blue light;

the red light-emitting unit comprises a blue light-emitting chip for emitting blue light, a light-transmitting matrix layer positioned at one side of the blue light-emitting chip away from the driving substrate, and a red conversion material filled in a nano hole of the light-transmitting matrix layer; the red conversion material is used for emitting red light under excitation of blue light.

3. The display device according to claim 1, wherein the light emitting units are divided into a red light emitting unit, a green light emitting unit, and a blue light emitting unit;

the red light-emitting unit, the green light-emitting unit and the blue light-emitting unit comprise blue light-emitting chips for emitting blue light and transparent matrix layers positioned on one sides of the blue light-emitting chips, which are away from the driving substrate;

the red light emitting unit comprises a light-transmitting substrate layer, a red light-emitting layer and a red light-emitting layer, wherein a red conversion material is filled in the nano holes of the light-transmitting substrate layer of the red light-emitting unit, and is used for emitting red light under excitation of blue light; and the nano holes of the light-transmitting matrix layer of the green light-emitting unit are filled with a green conversion material, and the green conversion material is used for emitting green light under the excitation of blue light.

4. A display device as claimed in claim 2 or 3, wherein the red conversion material and the green conversion material are both quantum dot materials.

5. A display device as claimed in claim 2 or 3, characterized in that at least part of the light emitting unit further comprises:

the first filter layer is positioned between the light-emitting chip and the light-transmitting matrix layer; the first filter layer is used for transmitting blue light and reflecting red light and green light;

the first filter layer is a Bragg reflection layer.

6. The display device according to claim 5, wherein the light emitting chip includes:

the n-type doped layer is positioned at one side of the first optical filter layer, which is away from the transparent matrix layer;

the light-emitting layer is positioned at one side of the n-type doped layer, which is away from the first filter layer;

the p-type doped layer is positioned at one side of the light-emitting layer, which is away from the n-type doped layer; the light emitting layer and the p-type doped layer expose a portion of the n-type doped layer;

the dielectric layer is positioned on one side of the exposed n-type doped layer and one side of the p-type doped layer, which are away from the first filter layer; the dielectric layer comprises two through holes which respectively expose part of the n-type doped layer and part of the p-type doped layer;

And the two electrodes are respectively contacted with the exposed n-type doped layer and the exposed p-type doped layer through the two through holes.

7. The display device of claim 6, wherein the n-doped layer is an n-doped GaN layer and the p-doped layer is a p-doped GaN layer;

the light-transmitting substrate layer is an n-type heavily doped GaN layer, and the nano holes in the light-transmitting substrate layer are formed by adopting an electrochemical etching method.

8. The display device according to claim 5, further comprising:

and the passivation layer is positioned on the surface of one side of at least part of the light-emitting units, which is away from the driving substrate, and the side wall of the light-emitting units.

9. The display device according to claim 8, further comprising:

the second filter layer is positioned on the passivation layer on the surface and the side wall of the red light-emitting unit, which are away from one side of the driving substrate, or on the passivation layer on the surface and the side wall of the red light-emitting unit and the green light-emitting unit, which are away from one side of the driving substrate; the second filter layer is used for transmitting red light and green light and reflecting blue light;

the second filter layers are all Bragg reflection layers.

10. The display device according to claim 9, further comprising:

the bonding layer is positioned on the surface of one side of the second filter layer, which is away from the driving substrate;

and the packaging substrate is positioned on the surface of one side of the bonding layer, which is away from the driving substrate.