CN108878621B

CN108878621B - LED packaging structure, backlight module and display device

Info

Publication number: CN108878621B
Application number: CN201810642156.8A
Authority: CN
Inventors: 孟长军; 王强芳; 韩继远
Original assignee: Shenzhen Skyworth RGB Electronics Co Ltd
Current assignee: Shenzhen Skyworth RGB Electronics Co Ltd
Priority date: 2018-06-21
Filing date: 2018-06-21
Publication date: 2020-03-17
Anticipated expiration: 2038-06-21
Also published as: CN108878621A

Abstract

The invention discloses an LED packaging structure, a backlight module and display equipment. The LED packaging structure comprises a support and at least two LED chips, wherein the support is provided with at least two packaging grooves, and at least one LED chip is arranged in each packaging groove; and each packaging groove is filled with packaging material, and at most one quantum dot material is contained in each packaging groove. This LED encapsulation is through setting up two at least encapsulation grooves, and every encapsulation inslot includes a quantum dot material at most, can guarantee the stability of quantum dot material to avoid appearing many colourity and the condition that luminance attenuates by a wide margin, guarantee LED packaging structure's color rendering index, improve backlight unit and display device's display effect.

Description

LED packaging structure, backlight module and display device

Technical Field

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

Background

As shown in fig. 1, the conventional LED package structure mainly includes a support 1 ', an LED chip 2 ', and a phosphor layer 3 '. A bowl cup is arranged in the support 1 ', the LED chip 2' is fixed in the bowl cup through glue, the fluorescent powder layer 3 'is filled in the bowl cup through a glue dispensing mode to seal the LED chip 2', and light emitted by the LED chip 2 'excites the fluorescent powder layer 3' to form white light. However, the conventional LED package structure generally excites the yellow phosphor layer through the blue LED chip, which causes problems of low color rendering index and low phosphor excitation efficiency.

The color rendering index refers to the color rendering property of an object irradiated by a light source. The color rendering index of an object under natural light is defined as 100, and the color rendering index of the LED packaging structure of the traditional blue LED chip excited yellow fluorescent powder is 70 through tests.

Quantum dots (Quantum dots), also known as nanocrystals, are nanoparticles composed of elements of groups II-VI or III-V. The particle size of the quantum dot is generally between 1-10nm, and because electrons and holes are limited by quanta, a continuous energy band structure is changed into a discrete energy level structure with molecular characteristics, and the quantum dot can emit fluorescence after being excited. The emission spectrum of the quantum dots can be controlled by varying the size of the quantum dots. The size and chemical composition of the quantum dot can be changed to enable the emission spectrum to cover the whole visible light region, so that the quantum dot has a wide excitation spectrum and a narrow emission spectrum, and the spectral coverage rate is high. Compared with the fluorescent life of organic fluorescent powder, the fluorescent life of the quantum dot is 3-5 times that of the organic fluorescent powder, the quantum dot has good light stability, and in all, the quantum dot is an ideal fluorescent material.

At present, quantum dots are applied to an LED packaging structure in the industry, and a blue LED chip is utilized to excite a mixed material of red quantum dots and green quantum dots to generate white light, so that the white light with high color rendering property can be obtained. However, the wavelength of light emitted by the quantum dot material is determined according to the size of the nanoparticle, and after a plurality of quantum dot materials are mixed, the situation of large-scale reduction of chromaticity and brightness can occur in practical verification, because the stability of the short-wavelength blue quantum dot material is poor, and meanwhile, the stability of the plurality of quantum dot materials is difficult to guarantee at the same time by adding the plurality of quantum dot materials into the LED package structure, so that the quantum dot LED package structure is difficult to realize normal mass production.

Disclosure of Invention

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

In order to achieve the purpose, the invention adopts the following technical scheme:

an LED packaging structure comprises a support and at least two LED chips, wherein the support is provided with at least two packaging grooves, and at least one LED chip is arranged in each packaging groove;

and each packaging groove is filled with packaging material, and at most one quantum dot material is contained in each packaging groove.

And at least two packaging grooves are covered with diffusion layers.

The support is provided with a groove, a blocking rib is arranged in the groove, and the blocking rib divides the groove into at least two packaging grooves.

The height of the partition rib is smaller than the depth of the groove, and the diffusion layer is arranged in a space above the partition rib of the groove.

Wherein, separate disconnected muscle with support integrated into one piece.

The LED chip is an ultraviolet LED chip, a red LED chip, a blue LED chip or a green LED chip;

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

Wherein the packaging material in the packaging groove provided with the ultraviolet LED chip is covered with an ultraviolet absorption layer.

The packaging groove is divided into an upper groove body and a lower groove body by the step surface, the upper groove body is used for containing the ultraviolet absorption layer, and the lower groove body is used for containing the packaging material.

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

a backlight module comprises the LED packaging structure.

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

a display device comprises a display panel and further comprises the backlight module.

Has the advantages that: the invention provides an LED packaging structure, a backlight module and display equipment. This LED encapsulation is through setting up two at least encapsulation grooves, and every encapsulation inslot includes a quantum dot material at most, can guarantee the stability of quantum dot material to avoid appearing many colourity and the condition that luminance attenuates by a wide margin, guarantee LED packaging structure's color rendering index, improve backlight unit and display device's display effect.

Drawings

FIG. 1 is a cross-sectional view of a prior art LED package structure;

fig. 2 is a cross-sectional view of an LED package structure provided in embodiment 1 of the present invention;

fig. 3 is a schematic structural diagram of an LED chip and a support provided in embodiment 1 of the present invention;

fig. 4 is a top view of an LED chip and a support provided in embodiment 1 of the present invention;

FIG. 5 is a sectional view taken along line A-A of FIG. 4;

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

fig. 7 is a schematic structural diagram of an LED chip and a support provided in embodiment 2 of the present invention;

fig. 8 is a top view of an LED chip and a support provided in embodiment 2 of the present invention.

Wherein:

1. a support; 11. separating ribs; 111. a step surface; 12. a groove; 2. an LED chip; 3. packaging materials; 4. an ultraviolet absorbing layer; 5. a diffusion layer; 6. an electrode;

1', a bracket; 2', an LED chip; 3', and a fluorescent powder layer.

Detailed Description

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

Example 1

The embodiment provides a display device which can be a television, a display, an advertising machine and the like. The display device comprises a display screen and a backlight module, wherein the backlight module supplies sufficient light sources with uniform brightness and distribution for the display panel, so that the display panel can normally display images.

In this embodiment, the backlight module mainly includes a back plate, a reflective sheet, a light bar, and an optical film. The optical diaphragm is arranged above the back plate, the light bar can be arranged on the back plate in a double-faced adhesive tape, screw or buckle mode, and the light bar comprises a PCB and an LED packaging structure. Specifically, the PCB is long-strip-shaped, a plurality of LED packaging structures are arranged on the PCB along the length direction, and light rays emitted by the LED packaging structures are uniformly diffused by the optical diaphragm to form a uniform illumination area on the display panel. The reflector plate can reflect light rays to the direction of the optical film, so that the utilization rate of the light rays is improved.

As shown in fig. 2, the LED package structure includes a support 1, an LED chip 2, and an encapsulation material 3. A groove 12 is formed in the support 1 in an inward concave mode, the LED chip 2 is fixed in the groove 12, and the groove 12 is filled with the packaging material 3 to seal the LED chip 2. The support 1 is also provided with an electrode 6, and the electrode 6 is electrically connected with the PCB. In operation, light generated by the LED chip 2 excites the encapsulant 3, and polychromatic light is mixed to form white light. Alternatively, the cross-sectional shape of the groove 12 may be a polygon such as a rectangle, a triangle, etc., or may be a circle or an ellipse. The LED chip 2 may be bonded to the bottom surface of the groove 12 by glue, wherein the glue may be die bond glue.

In order to improve the color rendering index of the LED package structure, the packaging material 3 may be a quantum dot material. Because the LED chip 2 needs to excite the package material 3 to generate three color lights, i.e., green light, red light, and blue light, and the stability of the mixed quantum dots is poor, the problem of multi-chromaticity and substantial brightness attenuation is likely to occur, in this embodiment, the LED package structure is improved to solve the above problem.

Specifically, as shown in fig. 2 and 3, the groove 12 of the bracket 1 is divided into two packaging grooves, each packaging groove is filled with the packaging material 3 and the at least one LED chip 2, the packaging material 3 in the at least one packaging groove is a quantum dot material, so as to ensure the color rendering index of the LED packaging material 3, and at most one quantum dot material is included in each packaging groove. By arranging the two packaging grooves, at least three color lights of green light, red light and blue light can be excited in the two packaging grooves, so that white light can be formed by mixing. The size and number of the LED chips 2 in each package slot can be adjusted according to the actual brightness and color temperature. The packaging groove comprises at most one quantum dot material, so that the mixing of multiple quantum dot materials can be avoided, the stability of the quantum dot materials is ensured, the problem of large-amplitude attenuation of multi-chromaticity and brightness is avoided, and the light source effect of the backlight module and the display effect of the display device are improved.

Alternatively, 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 encapsulating material 3 may be a silica gel mixed with a phosphor or quantum dot material. The fluorescent powder can be red fluorescent powder, green fluorescent powder and blue fluorescent powder, and the quantum dot material can be green quantum dots, blue quantum dots and red quantum dots. The red quantum dots and the red fluorescent powder are excited to generate red light, the green quantum dots and the green fluorescent powder are excited to generate green light, and the blue fluorescent powder is excited to generate blue light. Through the combination of the LED chips 2 and the packaging materials 3, the LED chips 2 in the two packaging grooves and the corresponding packaging materials 3 can be combined to form three color lights of green light, red light and blue light, so that white light is formed by mixing.

Optionally, the red phosphor is a fluoride phosphor, such as KSF phosphor and KGF phosphor. The red quantum dot material can be a nanocrystal quantum dot composed of cadmium selenide (CdSe) and zinc sulfide (ZnS), and the green quantum dot material can be a nanocrystal quantum dot composed of cadmium selenide (CdSe), cadmium sulfide (CdS) and zinc sulfide (ZnS).

In this embodiment, each package slot is correspondingly provided with one LED chip 2. 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. Ultraviolet rays emitted by the ultraviolet LED chip have higher energy, and better luminous efficiency can be obtained when the quantum dot material or the fluorescent powder is excited, so that the color rendering of the LED packaging structure is improved.

Optionally, the encapsulating material 3 matched with the ultraviolet LED chip may be a quantum dot material, or may be a phosphor. Taking the packaging material 3 matched with the ultraviolet LED chips as a red quantum dot material as an example, one of the two packaging grooves is provided with the ultraviolet LED chips and packaged by the red quantum dot material, and the ultraviolet rays emitted by the ultraviolet LED chips can excite the red quantum dot material to generate red light; correspondingly, green and blue light needs to be generated in the other package slot. Optionally, another packaging groove may be provided with a blue LED chip and packaged with a green phosphor or a green quantum dot material, the blue LED chip will generate high-purity blue light, and excitation of the green phosphor or the green quantum dot will also generate green light. In addition, a green light LED chip can be arranged and packaged by blue fluorescent powder, the green light LED chip can generate high-purity green light, the blue fluorescent powder is excited to generate blue light, and the blue light, the green light and the red light are mixed to obtain white light.

According to the collocation principle, the LED chips 2 and the packaging materials 3 in the two packaging grooves can be collocated in various ways as long as the requirement that one quantum dot material is filled in each packaging groove at most is met, and the two packaging grooves can excite blue light, green light and red light three-color light. The quantum dot material is preferably red quantum dot or green quantum dot due to poor stability of blue quantum dot. Since the green phosphor is excited to generate green light with low saturation, the phosphors are preferably red and blue phosphors.

The three colors of light produced by the two package wells need to be mixed to form white light. In order to improve the mixing effect of the three colors of light, the two packaging grooves can be covered with a diffusion layer 5. 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, the groove 12 is provided with a partition rib 11, and the partition rib 11 is in a strip shape, so that the groove 12 is divided into two packaging grooves. The height of the blocking ribs 11 is smaller than the depth of the grooves 12, and the spaces of the grooves 12 above the blocking ribs 11 are used for arranging the diffusion layers 5. The upper ends of the two packaging grooves are communicated, and the diffusion layer 5 is arranged at the communication position of the upper ends of the two packaging grooves, so that the multicolor light is ensured to be uniformly mixed.

Because the ultraviolet LED chip can generate ultraviolet light in addition to the monochromatic light generated by the encapsulating material 3, for this purpose, the encapsulating material 3 of the encapsulating groove provided with the ultraviolet LED chip can also be provided with an ultraviolet absorbing layer 4, thereby absorbing the redundant ultraviolet light.

In this embodiment, the phosphor and the quantum dot material may be dissolved in the organic silicon solvent, and may be filled into the groove 12 by a dispensing method. As shown in fig. 4 to 6, for convenience of dispensing, the inner wall of the packaging groove provided with the ultraviolet LED chip may be a stepped surface 111. Specifically, as shown in fig. 6, one side wall of the blocking rib 11 is a stepped surface 111, and the stepped surface 111 divides the sealing groove into an upper groove body and a lower groove body, wherein the lower groove body is used for accommodating the sealing material 3, and the upper groove body is used for accommodating the ultraviolet absorption layer 4. The height of the packaging layer and the ultraviolet absorption layer 4 can be conveniently controlled through the step surface 111, so that the absorption effect of light and ultraviolet generated by the packaging layer is controlled.

In this embodiment, the blocking rib 11 may be integrally formed with the bracket 1. The stent 1 may be injection molded from polyphosphoric acid (PPA), polycyclohexylenedimethylene terephthalate resin, Epoxy Molding Compound (EMC) or smc (sheet Molding Compound) composite material, or the stent 1 may be fired from ceramic material.

In order to make the light reflected 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 to improve the utilization rate of the light. In order to obtain a wider range of exit angles, the side walls of the groove 12 and the side walls of the blocking ribs 11 can be inclined planes, so that the openings of the groove 12 and each packaging groove are expanded to increase the exit angle of light rays.

Alternatively, the LED chip 2 may be a flip chip or a front chip. When the LED chip 2 is in a flip structure, the LED chip 2 may be electrically connected to the support 1 through solder. When the LED chip 2 is of a normal mounting structure, the LED chip 2 may be electrically connected to the support 1 by gold wires.

In this embodiment, the two LED chips 2 used in the LED package structure are an ultraviolet LED chip and a blue LED chip, respectively, and since the blue quantum dot material has poor stability, the green phosphor is excited to generate monochromatic light with low saturation, in this embodiment, the package material 3 corresponding to the ultraviolet LED chip is selected as the green quantum dot material, and the package material 3 corresponding to the blue LED chip is selected as the red phosphor. The specific packaging method mainly comprises the following steps:

first, materials for the sealing material 3, the ultraviolet absorbing layer 4, and the diffusion layer 5 are prepared. Taking a green quantum dot material as an example, 1 part by weight of quantum dot fluorescent powder is added with 100-3000 parts by weight of organic solvent, and then the organic solvent with quantum dots is subjected to vibration treatment to obtain a quantum dot solution. And (3) uniformly mixing the quantum dot solution and the silica gel, and then carrying out a vacuum defoaming process. Wherein, the particle diameter of the nano-particles of the green quantum dot material is 1-10nm, and the wavelength of the light wave after being excited by the ultraviolet LED chip is 520-540 nm. The material of the ultraviolet absorption layer 4 can be selected from rare earth fluorescent materials, and the rare earth fluorescent powder material can absorb ultraviolet light and generate green light.

And then, respectively fixing the ultraviolet LED chip and the blue LED chip in the two packaging grooves. And (4) dropping the green quantum dot material and the red fluorescent powder into the two packaging grooves in sequence by a dispensing mode, and baking. And (3) dripping rare earth fluorescent powder into the packaging groove provided with the ultraviolet LED chip, and baking to form the ultraviolet absorption layer 4. 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 having substantially the same structure as that of embodiment 1, except that the stand 1 has three package grooves, unlike embodiment 1.

As shown in fig. 7 and 8, the partition ribs 11 in the groove 12 are Y-shaped, which partition the groove 12 into three package grooves, each of which correspondingly generates one of green light, red light and blue light, and the white light is formed by mixing the monochromatic lights in the three package grooves.

In order to improve the uniformity of the mixing of the multi-color light, the partition ribs 11 may uniformly divide the groove 12 into three package grooves. When the number of the packaging grooves is three, ultraviolet LED chips can be arranged in each packaging groove, and each ultraviolet LED chip excites different packaging materials 3 to respectively generate red, green and blue light, so that white light can be mixed. Specifically, the encapsulating materials 3 in the three encapsulating grooves may be a red light quantum dot material, a green light quantum dot material and a blue fluorescent powder, respectively.

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

The above description is only a preferred embodiment of the present invention, and for those skilled in the art, the present invention should not be limited by the description of the present invention, which should be interpreted as a limitation.

Claims

1. The LED packaging structure is characterized by comprising a support (1) and at least two LED chips (2), wherein a groove (12) is formed in the support (1), a blocking rib (11) is arranged in the groove (12), the groove (12) is uniformly divided into three packaging grooves by the blocking rib (11) around the center of the groove, and at least one LED chip (2) is arranged in each packaging groove;

each packaging groove is filled with packaging material (3), and each packaging groove at most comprises one quantum dot material;

the height of the blocking rib (11) is smaller than the depth of the groove (12), and a diffusion layer (5) is arranged in a space, above the blocking rib (11), of the groove (12);

and reflecting layers are arranged on the inner wall of the groove (12) and the outer surface of the blocking rib (11).

2. The LED package structure of claim 1, wherein the breaking rib (11) is integrally formed with the support (1).

3. The LED package structure according to claim 1, wherein the LED chip (2) is an ultraviolet LED chip, a red LED chip, a blue LED chip, or a green LED chip;

at least one of the at least three LED chips (2) is the ultraviolet LED chip.

4. The LED package structure according to claim 3, wherein the packaging material (3) in the packaging groove in which the ultraviolet LED chip is disposed is covered with an ultraviolet absorption layer (4).

5. The LED packaging structure according to claim 4, wherein at least one inner wall of the packaging groove in which the ultraviolet LED chip is disposed is a step surface (111), the step surface (111) divides the packaging groove into an upper groove body and a lower groove body, the upper groove body is used for accommodating the ultraviolet absorption layer (4), and the lower groove body is used for accommodating the packaging material (3).

6. A backlight module comprising the LED package structure of any one of claims 1-5.

7. A display device comprising a display panel, further comprising the backlight module of claim 6.