CN108878621B - LED packaging structure, backlight module and display device - Google Patents

Abstract

The invention discloses an LED packaging structure, a backlight module and a display device. The LED packaging structure includes a bracket and at least two LED chips, the bracket is provided with at least two packaging grooves, each of the packaging grooves is provided with at least one of the LED chips; each of the packaging grooves is filled with packaging materials, and each of the packaging grooves includes at most one quantum dot material. The LED package is provided with at least two packaging grooves, and each packaging groove contains at most one quantum dot material, which can ensure the stability of the quantum dot material, thereby avoiding the occurrence of multi-chromaticity and large attenuation of brightness, ensuring the LED The color rendering index of the package structure improves the display effect of the backlight module and the display device.

Description

An LED package structure, a backlight module and a display device

technical field

The present invention relates to the technical field of display devices, in particular to an LED packaging structure, a backlight module and a display device.

Background technique

As shown in FIG. 1 , a conventional LED packaging structure mainly includes a bracket 1 ′, an LED chip 2 ′ and a phosphor layer 3 ′. The bracket 1' is provided with a bowl, the LED chip 2' is fixed in the bowl by glue, and the phosphor layer 3' is filled into the bowl by dispensing glue to seal the LED chip 2'. The light excites the phosphor layer 3' to form white light. However, the traditional LED packaging structure generally excites the yellow phosphor layer through the blue LED chip, which has the problems of low color rendering index and low phosphor excitation efficiency.

The color rendering index refers to the light source illuminated on the object, and the color rendering ability of the object is called color rendering. We define the color rendering index of objects under natural light as 100, and the color rendering index of the LED package structure of the traditional blue LED chip excited yellow phosphor is 70.

Quantum dots (Quantum Dot), also known as nanocrystals, are nanoparticles composed of II-VI or III-V elements. The particle size of quantum dots is generally between 1 and 10 nm. Due to the quantum confinement of electrons and holes, the continuous energy band structure becomes a discrete energy level structure with molecular characteristics, which can emit fluorescence after excitation. The emission spectrum of quantum dots can be controlled by changing the size of the quantum dots. By changing the size of quantum dots and its chemical composition, its emission spectrum can cover the entire visible light region, with a broad excitation spectrum and a narrow emission spectrum, so the spectral coverage is high. Moreover, compared with the fluorescence lifetime of organic phosphors, the fluorescence lifetime of quantum dots is 3-5 times longer, and has good photostability. All in all, quantum dots are an ideal fluorescent material.

At present, quantum dots are applied in the LED packaging structure in the industry, and the mixed materials of red quantum dots and green quantum dots are excited by blue LED chips to generate white light, and white light with high color rendering can be obtained. However, since the wavelength of light emitted by quantum dot materials is determined according to the size of the nanoparticles, after a variety of quantum dot materials are mixed, the multi-chromaticity and brightness will be greatly attenuated in the actual verification. The reason is that the short-wavelength blue The stability of quantum dot materials is relatively poor, and at the same time, a variety of quantum dot materials are added to the LED packaging structure.

SUMMARY OF THE INVENTION

One object of the present invention is to provide an LED packaging structure, which can ensure the stability of quantum dot materials and avoid chromaticity and brightness attenuation.

For this purpose, the present invention adopts the following technical solutions:

An LED packaging structure includes a bracket and at least two LED chips, the bracket is provided with at least two packaging grooves, and each of the packaging grooves is provided with at least one of the LED chips;

Each of the packaging grooves is filled with packaging material, and each packaging groove includes at most one quantum dot material.

Wherein, at least two of the packaging grooves are covered with diffusion layers.

Wherein, the bracket is provided with a groove, the groove is provided with a partition rib, and the partition rib divides the groove into at least two packaging grooves.

Wherein, the height of the partition rib is less than the depth of the groove, and the diffusion layer is provided in the space above the partition rib of the groove.

Wherein, the partition rib and the bracket are integrally formed.

Wherein, the LED chip is an ultraviolet LED chip, a red light LED chip, a blue light LED chip or a green light LED chip;

Among the at least two LED chips, at least one is an ultraviolet LED chip.

Wherein, the packaging material in the packaging groove in which the UV LED chip is disposed is covered with an UV absorbing layer.

Wherein, at least one inner wall of the packaging groove where the ultraviolet LED chip is arranged is a stepped surface, and the stepped surface divides the packaging groove into an upper groove body and a lower groove body, and the upper groove body is used to accommodate the the ultraviolet absorbing layer, and the lower tank body is used for accommodating the packaging material.

Another object of the present invention is to provide a backlight module, in which the LED packaging structure can ensure the stability of the quantum dot material, avoid chromaticity and brightness attenuation, and thus ensure the brightness of the backlight module.

For this purpose, the present invention adopts the following technical solutions:

A backlight module includes the above-mentioned LED packaging structure.

Another object of the present invention is to provide a display device in which the brightness and chromaticity of the backlight module are stable and the display effect is good.

For this purpose, the present invention adopts the following technical solutions:

A display device includes a display panel, and also includes the above-mentioned backlight module.

Beneficial effects: The present invention provides an LED packaging structure, a backlight module and a display device. The LED package is provided with at least two packaging grooves, and each packaging groove includes at most one quantum dot material, which can ensure the stability of the quantum dot material, thereby avoiding the occurrence of multi-chromaticity and large attenuation of brightness, ensuring the LED The color rendering index of the package structure improves the display effect of the backlight module and the display device.

Description of drawings

1 is a cross-sectional view of an LED package structure in the prior art;

2 is a cross-sectional view of the LED package structure provided in Embodiment 1 of the present invention;

3 is a schematic structural diagram of an LED chip and a bracket provided in Embodiment 1 of the present invention;

4 is a top view of the LED chip and the bracket provided in Embodiment 1 of the present invention;

Fig. 5 is A-A sectional view in Fig. 4;

Fig. 6 is a partial enlarged view at B in Fig. 5;

7 is a schematic structural diagram of an LED chip and a bracket provided in Embodiment 2 of the present invention;

8 is a top view of the LED chip and the bracket provided in Embodiment 2 of the present invention.

in:

1. Bracket; 11. Partitioning ribs; 111. Step surface; 12. Groove; 2. LED chip; 3. Packaging material; 4. Ultraviolet absorption layer; 5. Diffusion layer; 6. Electrode;

1', bracket; 2', LED chip; 3', phosphor layer.

Detailed ways

In order to make the technical problems solved by the present invention, the technical solutions adopted and the technical effects achieved more clearly, the technical solutions of the present invention are further described below with reference to the accompanying drawings and through specific embodiments.

Example 1

This embodiment provides a display device, and the display device may be a television, a display, an advertising machine, or the like. The display device includes a display screen and a backlight module. The backlight module supplies the display panel with sufficient brightness and a uniformly distributed light source, so that it can display images normally.

In this embodiment, the backlight module mainly includes a backplane, a reflector, a light bar and an optical film. The optical film is arranged above the backboard, the light bar can be arranged on the backboard by means of double-sided tape, screws or snaps, and the light bar includes a PCB board and an LED packaging structure. Specifically, the PCB board is in the shape of a strip, and a plurality of LED packaging structures are arranged on the PCB board along the length direction. After the light emitted by the LED packaging structures is evenly diffused by the optical film, a uniform illumination area is formed on the display panel. The reflective sheet can reflect light to the direction of the optical film, thereby improving the utilization of light.

As shown in FIG. 2 , the LED packaging structure includes a bracket 1 , an LED chip 2 and a packaging material 3 . A groove 12 is concavely formed on the bracket 1 , the LED chip 2 is fixed in the groove 12 , and the groove 12 is filled with a packaging material 3 to seal the LED chip 2 . An electrode 6 is also provided on the bracket 1, and the electrode 6 is electrically connected to the PCB board. During operation, the light generated by the LED chip 2 excites the packaging material 3, and the multi-color light is mixed to form white light. Optionally, the cross-sectional shape of the groove 12 may be a polygon such as a rectangle or a triangle, or may be a circle or an ellipse. The LED chip 2 can be adhered to the bottom surface of the groove 12 by glue, wherein the glue can be die-bonding glue.

In order to improve the color rendering index of the LED packaging structure, the packaging material 3 can use quantum dot material. Since the LED chip 2 excites the encapsulation material 3 to generate green light, red light and blue light, the stability of mixing various quantum dots is poor, and the problems of multi-chromaticity and brightness attenuation are prone to occur. Therefore, In this embodiment, the LED packaging structure is improved to solve the above problems.

Specifically, as shown in FIGS. 2 and 3 , the groove 12 of the bracket 1 is divided into two encapsulation slots, each encapsulation slot is filled with the encapsulation material 3 and at least one LED chip 2 correspondingly, and the at least one encapsulation slot is filled with the encapsulation material 3 and the at least one LED chip 2 correspondingly. The packaging material 3 is a quantum dot material, so as to ensure the color rendering index of the LED packaging material 3, and each packaging groove includes at most one quantum dot material. By arranging two packaging grooves, it can be ensured that at least three color lights of green light, red light and blue light can be excited in the two packaging grooves, so as to be mixed to form white light. The size and quantity of the LED chips 2 in each package slot can be adjusted according to the actual required brightness and color temperature. Each encapsulation slot contains at most one quantum dot material, which can avoid the mixing of multiple quantum dot materials, thereby ensuring the stability of the quantum dot material, thereby avoiding the problems of multi-chromaticity and large brightness attenuation, and improving the backlight module’s performance. Lighting effects and display effects of display devices.

Optionally, the LED chip 2 may be a blue LED chip, a red LED chip, a green LED chip or an ultraviolet LED chip. The blue LED chip, the red LED chip and the green LED chip can respectively obtain monochromatic light with high saturation. The packaging material 3 may be silica gel mixed with phosphor powder or quantum dot material. Wherein, the phosphors can be red phosphors, green phosphors and blue phosphors, and the quantum dot materials can be green quantum dots, blue quantum dots and red quantum dots. Red quantum dots and red phosphors are excited to produce red light, green quantum dots and green phosphors are excited to produce green light, and blue phosphors are excited to produce blue light. Through the combination of the LED chip 2 and the packaging material 3, the LED chips 2 in the two packaging grooves and the corresponding packaging material 3 can be combined to form green light, red light and blue light, thereby mixing to form white light.

Optionally, the red phosphors are fluoride phosphors, such as KSF phosphors and KGF phosphors. The red quantum dot material can be nanocrystalline quantum dots composed of cadmium selenide (CdSe) and zinc sulfide (ZnS), and the green quantum dot material can be composed of cadmium selenide (CdSe), cadmium sulfide (CdS) and zinc sulfide (ZnS) of nanocrystalline quantum dots.

In this embodiment, one LED chip 2 is correspondingly disposed in each packaging groove. In order to further improve the color rendering of the LED package structure, one of the two LED chips 2 is an ultraviolet LED chip. The ultraviolet light emitted by the ultraviolet LED chip has higher energy, and better light efficiency can be obtained when the quantum dot material or phosphor is excited, thereby improving the color rendering of the LED package structure.

Optionally, the packaging material 3 matched with the ultraviolet LED chip may be a quantum dot material or a phosphor powder. Taking the packaging material 3 of the UV LED chip as an example of red quantum dot material, one of the two packaging grooves is provided with a UV LED chip and is packaged with a red quantum dot material. The ultraviolet light emitted by the UV LED chip can excite the red quantum dot material to produce red light. ; Correspondingly, green light and blue light need to be generated in another package groove. Optionally, another encapsulation tank can be provided with a blue LED chip and encapsulated with green phosphor or green quantum dot material. The blue LED chip will generate high-purity blue light, and excited green phosphor or green quantum dot will also generate green light. Light. In addition, a green LED chip can also be set and packaged with blue phosphor powder. The green LED chip will generate high-purity green light, and the blue phosphor will be excited to generate blue light, and blue light, green light and red light will be mixed. White light can be obtained.

According to the above matching principle, the LED chip 2 and the packaging material 3 in the two packaging grooves can also be matched in various ways, as long as each packaging groove is filled with at most one quantum dot material, and the two packaging grooves can excite blue light and green light. Light and red light can be trichromatic light. Due to the poor stability of blue quantum dots, the quantum dot material is preferably red quantum dots or green quantum dots. Since the green light generated by the excited green phosphors has lower saturation, the phosphors are preferably red phosphors and blue phosphors.

The three colors of light generated by the two encapsulation troughs need to be mixed to form white light. In order to improve the mixing effect of the three colors of light, a diffusion layer 5 may also be covered on the two encapsulation grooves. The diffusion layer 5 may be a silica gel layer containing diffusion powder, and the diffusion layer 5 is mainly used for mixing multicolor light.

Specifically, a partition rib 11 is provided in the groove 12 , and the partition rib 11 is elongated, so that the groove 12 is divided into two packaging grooves. The height of the partition rib 11 is smaller than the depth of the groove 12 , and the space above the partition rib 11 of the groove 12 is used for disposing the diffusion layer 5 . The upper ends of the two encapsulation grooves are connected, and the diffusion layer 5 is arranged at the communication position of the upper ends of the two encapsulation grooves, so as to ensure uniform mixing of multicolor light.

Since the ultraviolet LED chip will generate ultraviolet light in addition to the monochromatic light generated by exciting the packaging material 3, for this reason, an ultraviolet absorption layer 4 may also be provided on the packaging material 3 provided with the packaging groove of the ultraviolet LED chip, so as to absorb excess light. of ultraviolet light.

In this embodiment, the phosphor powder and the quantum dot material can be dissolved in an organic silicon solvent, and can be filled into the groove 12 by dispensing. As shown in FIGS. 4-6 , in order to facilitate dispensing, the inner wall of the packaging groove in which the ultraviolet LED chip is disposed may be a stepped surface 111 . Specifically, as shown in FIG. 6 , one side wall of the partition rib 11 is a stepped surface 111 , and the stepped surface 111 divides the packaging groove into an upper groove body and a lower groove body. The lower groove body is used to accommodate the packaging material 3 , and the upper groove The body serves to accommodate the ultraviolet absorbing layer 4 . Through the step surface 111 , the heights of the encapsulation layer and the ultraviolet absorption layer 4 can be easily controlled, so as to control the light generated by the encapsulation layer when excited and the absorption effect of ultraviolet rays.

In this embodiment, the partition rib 11 can be integrally formed with the bracket 1 . The stent 1 can be injection-molded from polyphosphoric acid (PPA), polycyclohexamethylene terephthalate resin, epoxy molding compound (EMC) or SMC (Sheet Molding Compound) composite material Forming, the stent 1 can also be fired from a ceramic material.

In order to make the light reflect outward from the groove 12 as much as possible, the inner wall of the groove 12 and the outer surface of the partition rib 11 may be provided with a reflective layer, so as to improve the utilization rate of light. In order to obtain a wider range of outgoing angles, the sidewalls of the grooves 12 and the side walls of the partition ribs 11 can both be inclined planes, so that the openings of the grooves 12 and each packaging groove expand outward to increase the outgoing angle of light.

Optionally, the LED chip 2 may be a flip chip or a positive chip. When the LED chip 2 is a flip-chip structure, the LED chip 2 can be electrically connected to the bracket 1 by soldering. When the LED chip 2 is in a positive mounting structure, the LED chip 2 can be electrically connected to the bracket 1 through a gold wire.

In this embodiment, the two LED chips 2 used in the LED packaging structure are an ultraviolet LED chip and a blue light LED chip, respectively. Due to the poor stability of the blue quantum dot material, the monochromatic light saturation generated by the excited green phosphor is low. In the embodiment, the packaging material 3 corresponding to the ultraviolet LED chip is selected as a green quantum dot material, and the packaging material 3 corresponding to the blue LED chip is selected as a red phosphor. The specific packaging methods mainly include:

First, materials for the encapsulating material 3 , the ultraviolet absorbing layer 4 , and the diffusion layer 5 are prepared. Taking the green quantum dot material as an example, adding 100-3000 parts by weight of an organic solvent to 1 part by weight of the quantum dot phosphor, and then vibrating the organic solvent with the quantum dots to obtain a quantum dot solution. The quantum dot solution and the silica gel are uniformly mixed and then subjected to a vacuum de-bubbling process. Among them, the particle size of the nanoparticles of the green quantum dot material is 1-10 nm, and the wavelength of the light wave after being excited by the ultraviolet LED chip is 520-540 nm. The material of the ultraviolet absorbing layer 4 can be selected as a rare earth fluorescent material, and the rare earth fluorescent powder material can absorb ultraviolet light and generate green light.

After that, the ultraviolet LED chip and the blue LED chip are respectively fixed in the two packaging grooves. The green quantum dot material and the red phosphor are sequentially dropped into the two encapsulation grooves by means of dispensing for baking. The rare earth phosphor powder is dropped into the packaging tank provided with the ultraviolet LED chip, and the ultraviolet absorbing layer 4 is formed by baking. Finally, a solvent containing diffusion powder is dropped into the groove 12, and the diffusion layer 5 is formed after baking.

Example 2

This embodiment provides a display device, which is substantially the same in structure as the display device in Embodiment 1, and differs from Embodiment 1 in that the bracket 1 has three packaging grooves.

As shown in FIG. 7 and FIG. 8 , the partition rib 11 in the groove 12 is Y-shaped, which divides the groove 12 into three packaging grooves, and each packaging groove generates green light, red light and blue light correspondingly. A monochromatic light that forms white light by mixing the monochromatic light in the three encapsulation grooves.

In order to improve the uniformity of mixing of multi-colored light, the partition rib 11 can evenly divide the groove 12 into three packaging grooves. When there are three encapsulation slots, each encapsulation slot can be provided with an ultraviolet LED chip, and each ultraviolet LED chip excites a different encapsulation material 3 and generates red, green and blue light respectively, which can be mixed into white light. Specifically, the packaging materials 3 in the three packaging grooves may be red light quantum dot materials, green light quantum dot materials, and blue phosphors, respectively.

In other embodiments, the number of packaging slots may be four or more, and the type and number of LED chips 2 in each packaging slot and the type of packaging material 3 may also be adjusted according to actual conditions, and it is only necessary to ensure that each packaging slot is There is at most one quantum dot material inside, and the light generated by the multiple encapsulation grooves can be mixed into white light.

The above contents are only preferred embodiments of the present invention. For those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific embodiments and application scope. limits.

Claims (7)

1. An LED packaging structure, characterized in that it comprises a bracket (1) and at least two LED chips (2), wherein a groove (12) is provided on the bracket (1), and a groove (12) is provided in the groove (12). A partition rib (11) is provided, and the partition rib (11) evenly divides the groove (12) into three packaging grooves around the center thereof, and each of the packaging grooves is provided with at least one of the LED chips ( 2); Each of the encapsulation grooves is filled with an encapsulation material (3), and each of the encapsulation grooves includes at most one quantum dot material; The height of the partition rib (11) is less than the depth of the groove (12), and a diffusion layer (5) is provided in the space above the partition rib (11) of the groove (12); A reflection layer is provided on the inner wall of the groove (12) and the outer surface of the partition rib (11). 2 . The LED package structure according to claim 1 , characterized in that, the partition rib ( 11 ) and the bracket ( 1 ) are integrally formed. 3 . 3. The LED packaging structure according to claim 1, wherein the LED chip (2) is an ultraviolet LED chip, a red light LED chip, a blue light LED chip or a green light LED chip; Among the at least three LED chips (2), at least one is the ultraviolet LED chip. 4 . The LED packaging structure according to claim 3 , wherein the packaging material ( 3 ) in the packaging groove where the UV LED chip is disposed is covered with an ultraviolet absorption layer ( 4 ). 5 . 5. The LED packaging structure according to claim 4, characterized in that, at least one inner wall of the packaging groove in which the ultraviolet LED chip is arranged is a stepped surface (111), and the stepped surface (111) connects the The packaging groove is divided into an upper groove body and a lower groove body, the upper groove body is used for accommodating the ultraviolet absorbing layer (4), and the lower groove body is used for accommodating the packaging material (3). 6. A backlight module, characterized in that it comprises the LED package structure according to any one of claims 1-5. 7 . A display device, comprising a display panel, further comprising the backlight module of claim 6 . 8 .

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