CN114464604B - Display device, electronic equipment and packaging method of backlight module - Google Patents

Display device, electronic equipment and packaging method of backlight module Download PDF

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Publication number
CN114464604B
CN114464604B CN202110999324.0A CN202110999324A CN114464604B CN 114464604 B CN114464604 B CN 114464604B CN 202110999324 A CN202110999324 A CN 202110999324A CN 114464604 B CN114464604 B CN 114464604B
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Prior art keywords
light
packaging
backlight module
packaging adhesive
diffusion layer
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CN202110999324.0A
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CN114464604A (en
Inventor
袁高
郝俊龙
熊源
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Honor Device Co Ltd
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Honor Device Co Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L25/00—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof
    • H01L25/03—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes
    • H01L25/04—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes the devices not having separate containers
    • H01L25/075—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes the devices not having separate containers the devices being of a type provided for in group H01L33/00
    • H01L25/0753—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes the devices not having separate containers the devices being of a type provided for in group H01L33/00 the devices being arranged next to each other
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/48—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor body packages
    • H01L33/52—Encapsulations
    • H01L33/54—Encapsulations having a particular shape
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/48—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor body packages
    • H01L33/58—Optical field-shaping elements
    • H01L33/60—Reflective elements

Abstract

The application discloses display device, electronic equipment and a packaging method of a backlight module, which are used for solving the problems of low brightness, low contrast, halo effect and the like frequently occurring in the backlight module taking a Mini LED as a backlight source at present. Each Mini LED is packaged by independent packaging glue, and the packaging glue of any two packaged Mini LEDs is arranged at intervals. A diffusion layer and a light conversion film are sequentially stacked above the encapsulation adhesive along a first direction. The first direction is perpendicular to the substrate plate surface and extends towards the side where the Mini LED is located. The light output by the Mini LED can be output sequentially through the corresponding packaging adhesive, the diffusion layer and the light conversion film to provide backlight. The backlight module can improve the display effect of the display device, so that the user experience is improved.

Description

Display device, electronic equipment and packaging method of backlight module
The present application claims priority of the chinese patent application entitled "a Mini LED device and structure thereof" filed by the national intellectual property office at 7/16/2021, application number 202110806827.1, which is incorporated herein by reference in its entirety.
Technical Field
The present disclosure relates to backlight modules, and particularly to a display device, an electronic apparatus, and a method for packaging a backlight module.
Background
The display panels commonly available on the market are mainly classified into organic light-emitting diodes (OLEDs) and Liquid Crystal Displays (LCDs). The OLED displays by utilizing the self-luminous characteristic of each pixel, and the LCD controls whether the backlight output by the backlight module passes or not by the deflection of the liquid crystal, for example, when pure white is displayed, the liquid crystal 'lets' all the backlight; while displaying pure black, the liquid crystal "shades" the backlight. Therefore, the display principles of the two are completely different, the display effect of the LCD is slightly inferior to that of the OLED due to the difference, but the display image quality of the LCD can be greatly improved by the backlight module with high brightness and high contrast, so that the LCD can be compared with the OLED. Meanwhile, LCDs are lower in cost than OLEDs, and are therefore also used in large quantities in the market.
Generally, the LCD uses a Mini LED as a light source of the backlight module. However, the backlight module using the Mini LED as the backlight source often has the problems of low brightness, low contrast, halo effect and the like, resulting in poor display effect and greatly reducing user experience.
Disclosure of Invention
The application provides a display device, electronic equipment and a packaging method of a backlight module, which are used for solving the problems of low brightness, low contrast, halo effect and the like frequently occurring in the backlight module taking a Mini LED as a backlight source at present, and can improve the display effect of the display device, thereby improving the user experience.
In a first aspect, the present application provides a backlight module. The backlight module comprises a substrate and a plurality of Mini LEDs uniformly arranged on the substrate. Wherein, every Mini LED all glues the encapsulation through independent encapsulation, and the encapsulation that arbitrary two Mini LEDs correspond glues the interval setting. A diffusion layer and a light conversion film are sequentially stacked above the encapsulation adhesive along a first direction. The first direction is perpendicular to the substrate plate surface and extends towards the side where the Mini LED is located. The light output by the Mini LED can be output sequentially through the corresponding packaging adhesive, the diffusion layer and the light conversion film to provide backlight.
In the backlight module, the packaging glue of every two Mini LEDs is arranged at intervals, and air is filled between the packaging glue of every two Mini LEDs. The light reaching the side wall of the packaging glue is transmitted from the packaging glue serving as an optically dense medium to the air serving as an optically sparse medium, so that the light which is possibly totally reflected at the top of the packaging glue originally or is diffused and emitted into the area where the peripheral non-luminous Mini LED is positioned at the top of the packaging glue to cause a halo effect can be gathered to the optical axis of the Mini LED at the side wall of the packaging glue in a way of totally reflecting or deflecting towards the first direction, the halo effect is reduced, and the illuminance above the Mini LED is enhanced. As the intensity of light over the LEDs increases, this means that the greater the luminous flux over the Mini LED, the greater the light density, and thus the greater the uniformity of the intensity of light over the Mini LED, the greater the half intensity angle. With the increase of the half-intensity angle, the smaller the height of the Mini LED in the first direction required for achieving the illumination uniformity of the specific specification, the thinner the required backlight module is, and the thinner the display device is.
It should be understood that with the reduction of the halo effect, the area where the surrounding non-light-emitting Mini LED is located is not easily "lighted" by the light output by the light-emitting Mini LED, so that the area where the light-emitting Mini LED is located and the area where the non-light-emitting Mini LED is located can form a larger contrast, resulting in a high contrast. In addition, the side wall of the packaging adhesive totally reflects the large-angle light output by the Mini LED edge to the top of the packaging adhesive, so that the light gathering is increased, and the brightness of the backlight module can be improved.
In one possible design, the encapsulation adhesive is attached to the diffusion layer. When the packaging adhesive and the diffusion layer are attached, no air exists between the packaging adhesive and the diffusion layer. In this case, the light emitted from the top of the encapsulant directly enters the diffusion layer without entering the air first and then entering the diffusion layer by refraction of the air. Because the refracting index of diffusion layer is greater than the refracting index of air, consequently, compare in the light that gets into the air from the encapsulation glue top, from the light that the encapsulation glued top directly reachd the diffusion layer, be closer to first direction, the light of following the output of encapsulation glue top is more toward the center and assembles. In this way, the incident angle of the light reaching the diffusion layer is reduced, so that total reflection is less likely to occur, and the light collected toward the center is further away from the surrounding other non-emitting Mini LEDs.
Optionally, the refractive index of the encapsulation glue is smaller than the refractive index of the diffusion layer. In this case, the encapsulant is an optically thinner medium, and the diffusion layer is an optically denser medium. According to the definition of total reflection, the light is totally reflected when the light is incident from the optically dense medium to the optically sparse medium, and the light is not totally reflected when the light is incident from the optically sparse medium to the optically dense medium. Based on this, the light that incides to the encapsulation glue top will not take place the total reflection, but all refracts away through the diffusion barrier to reduced the emergence of total emission phenomenon, increased the transmission ratio (promptly the emergence efficiency) of light. In addition, since the light is emitted into the diffusion layer as the optically dense medium from the packaging adhesive as the optically sparse medium, the emitting angle of the light output from the top of the packaging adhesive can be reduced, in other words, the light output from the top of the packaging adhesive to the diffusion layer is gathered in the first direction instead of being diffused in the second direction, so that the phenomenon that the area where the surrounding non-luminous Mini LED is located is turned on due to light diffusion can be avoided, and further, the halo effect can be reduced.
Optionally, the width of the encapsulation glue in the second direction satisfies the following relation: l is 2 ＜L 1 +2h*tan(arcsin(n 2 /n 1 ). Wherein L is 2 The width of the packaging adhesive in the second direction; l is 1 The width of the Mini LED corresponding to the packaging glue in the second direction; h is the height of the packaging adhesive higher than the corresponding Mini LED in the first direction; n is 2 Is the refractive index of the diffusion layer; n is 1 Is the refractive index of the encapsulant. The second direction is the arrangement direction of the Mini LEDs. When L is 2 ＜L 1 +2h*tan(arcsin(n 2 /n 1 ) And when the light enters the diffusion layer from the top of the packaging adhesive, the width of the packaging layer is smaller than the total reflection position corresponding to the total reflection critical angle of the light incident to the diffusion layer from the top of the packaging adhesive. In this case, the incident angles of all the light rays incident on the top of the encapsulant will not exceed the critical angle of total reflection, so that the halo effect caused by the incident light rays with large incident angles on the top of the encapsulant and the emergent light rays with large emergent angles on the top of the encapsulant can be reduced.
In another possible embodiment, the encapsulation adhesive and the diffusion layer are arranged at intervals. A partition plate unit is connected between two adjacent packaging glues in the second direction, and the second direction is the arrangement direction of the Mini LEDs. The two adjacent packaging glues are a first packaging glue and a second packaging glue respectively. The partition board unit is provided with a first board surface facing the first packaging glue and a second board surface facing the second packaging glue. The first plate surface and the second plate surface have a light reflection function. The first packaging adhesive and the first board surface are arranged at intervals, and the second packaging adhesive and the second board surface are arranged at intervals. When the packaging adhesive and the diffusion layer are arranged at intervals, air exists between the packaging adhesive and the diffusion layer. Under the condition, the light emitted from the top of the packaging adhesive firstly enters the air, and then enters the diffusion layer after being diffused outwards (in the direction away from the optical axis of the Mini LED) through the air, so that the light in the central area of the Mini LED is diffused outwards, and the backlight module achieves better illumination uniformity. The larger the illuminance uniformity and the larger the half-intensity angle, the smaller the height of the Mini LED in the first direction required for reaching the illuminance uniformity of a specific specification, the thinner the required backlight module and the thinner the display device.
It should be understood that light that diffuses through the air is farther away from first direction, takes place the total reflection more easily or gets into the region at the position of the luminous Mini LED of periphery, causes the halo effect, and based on this, separate two adjacent encapsulation glues respectively through the first face and the second face of baffle unit, can avoid the mutual crosstalk of the light that different encapsulation glues transmitted to alleviate the halo effect when giving consideration to the illuminance uniformity. In some embodiments, a grid is disposed between the substrate and the diffusion layer. The grid has a plurality of grids. The single packaging adhesive is surrounded by the grid wall body of the single grid, and the grid wall body is a partition plate unit. The grid of grid has four grid wall bodies, therefore, when two adjacent encapsulating glues are located two adjacent grids respectively, the grid wall body of grid can enclose the encapsulating glue completely to can separate two adjacent encapsulating glues completely, thereby can avoid two adjacent encapsulating glues light that transmit to cross talk each other, arouse the halo effect.
In some embodiments, the spacer unit has a thickness in the second direction. The thickness of the separator units becomes gradually larger in the first direction. That is, the thickness of the grid wall gradually decreases from the end far from the substrate to the end near the substrate, and the grid wall has a structure with a wide top and a narrow bottom. Thus, light rays which may pass through the grid wall body are shielded and reflected by the extended part of the grid wall body through widening, so that the light rays cannot enter the surrounding non-luminous Mini LED, and the halo effect can be reduced.
Optionally, one end of the separator unit near the diffusion layer has a slope. The inclined surface is gradually close to the center line of the partition plate unit along the first direction. On one hand, the area of the top of the grid wall body, namely the area without light output can be reduced, so that the area of a black ring can be reduced, and the halo effect can be reduced; on the other hand, the light rays which are originally blocked and reflected by the grid wall body are incident to the top of the grid from the inclined plane, and the halo effect of the part caused by no light ray is compensated.
In other possible design schemes, an arc-shaped groove is formed in one side, close to the diffusion layer, of the packaging adhesive. After reaching the arc-shaped groove, the light output by the Mini LED is far away from the first direction deflection at the arc-shaped groove, so that the light is diffused towards the two sides of the optical axis, and the uniformity of illumination is further improved.
In other possible designs, the sidewall of the encapsulation glue gradually approaches the optical axis of the Mini LED corresponding to the encapsulation glue along the first direction. The side wall of the packaging adhesive refers to the top of the packaging adhesive except the top and the bottom of the packaging adhesive, and the top of the packaging adhesive refers to the side of the packaging adhesive close to the diffusion layer. The bottom of the packaging adhesive refers to the side of the packaging adhesive far away from the diffusion layer. That is, the side wall of the package glue is inclined towards the optical axis along the first direction to form a trapezoid side wall. Through inclining the packaging adhesive side wall to the optical axis, the normal line of the interface of the packaging adhesive side wall and the air can be deflected anticlockwise, and therefore the same light reaching the packaging adhesive side wall can be deflected towards the first direction finally. It should be understood that the light incident on the side wall of the package glue is substantially the high angle light from the edge of the Mini LED, and therefore, the trapezoidal side wall has the effect of making the high angle light from the edge of the Mini LED more convergent, further reducing the halo effect. In addition, after the light is deflected by the trapezoid side wall, the light can finally directly irradiate the gap between the grid wall body and the packaging adhesive, so that the brightness of the gap between the grid wall body and the packaging adhesive is improved, the light does not irradiate the grid wall body, and the area surrounded by the grid wall body is equivalent to a large-area uniform light source.
Optionally, the diffusion layer includes a diffusion plate, a diffusion film, and a brightness enhancement film stacked in the first direction. In other embodiments, the diffusion layer may also be a single-layer composite film, for example, a three-in-one film having the functions of a diffusion plate, a diffusion film, and a brightness enhancement film, so as to reduce the thickness of the backlight module.
In a second aspect, the present application further provides a display device. The display device includes: the display device comprises a display panel and the backlight module according to any one of the first aspect, wherein the display panel is stacked, and the backlight module is used for providing backlight for the display panel.
In a third aspect, the present application further provides an electronic device. The electronic device includes: the battery, the backlight module according to the first aspect, and the display panel are stacked in sequence. The backlight module is used for providing backlight for the display panel; the battery is respectively connected with the backlight module and the display panel and used for supplying power to the backlight module and the display panel.
In a fourth aspect, the present application further provides a method for packaging a backlight module, which is used for packaging the backlight module. The backlight module comprises a substrate and a plurality of Mini LEDs uniformly arranged on the substrate, the Mini LEDs and packaging glue corresponding to the Mini LEDs are arranged on the surface of the substrate along the row direction and the column direction. The method comprises the following steps: obtaining a first steel mesh; the first steel mesh comprises a plurality of first open pore areas and a plurality of first non-open pore areas, each first open pore area is provided with a first cavity and a first opening for pouring packaging glue into the corresponding first cavity, the first open pore areas and the first non-open pore areas are alternately arranged in the row direction and the column direction, and two adjacent first open pore areas in the row direction and two adjacent first open pore areas in the column direction are separated by the corresponding first non-open pore areas. A first steel mesh is laid over the substrate with the first open area aligned with the Mini LEDs and the first non-open area aligned with the gap between the two adjacent Mini LEDs. Pouring the packaging glue solution into the first cavity through the first opening to form corresponding packaging glue on each Mini LED; each Mini LED is packaged by independent packaging glue, and the packaging glue corresponding to two adjacent Mini LEDs in the row direction and the column direction is arranged at intervals.
In some embodiments, after the potting of the encapsulation adhesive is completed, the method further comprises: obtaining a second steel mesh; the second steel mesh comprises a plurality of second open-pore areas and a plurality of second non-open-pore areas, each second open-pore area is provided with a second cavity and a second opening for pouring grid glue solution into the corresponding second cavity, and the second non-open-pore areas and the second open-pore areas are alternately arranged in the row direction and the column direction; two adjacent second open regions in the row direction and two adjacent second open regions in the column direction are separated by a second non-open region. And laying the second steel mesh above the substrate, so that the second hole-opening area is aligned to the gap between two adjacent packaging glues, and the second non-hole-opening area covers the area where the packaging glue is located. Pouring the grid glue solution into the second cavity through the second opening to form a grid on the substrate; the grid is provided with a plurality of grids, the single packaging adhesive is surrounded by the grid wall body of the single grid, and a gap is formed between the grid wall body and the packaging adhesive. And performing light reflection treatment on the wall surface of the grid wall body facing the packaging adhesive.
In a fifth aspect, the present application further provides a method for packaging a backlight module, which is used for packaging the backlight module. The backlight module comprises a substrate and a plurality of Mini LEDs uniformly arranged on the substrate, the Mini LEDs and packaging glue corresponding to the Mini LEDs are arranged on the surface of the substrate along the row direction and the column direction. The method comprises the following steps: obtaining a third steel mesh; the third steel mesh is provided with a first surface and a second surface, wherein the third steel mesh comprises a plurality of boss areas and a plurality of third non-opening areas, each boss area comprises an arc-shaped boss structure and an opening area surrounding the arc-shaped boss structure, the arc-shaped boss structures protrude from the first surface to the second surface, and the opening areas are provided with third cavities and third openings for pouring packaging glue solution into the third cavities; the boss areas and the third non-hole-opening areas are alternately arranged in the row direction and the column direction; two land regions adjacent in the row direction and two land regions adjacent in the column direction are separated by a third non-apertured region. Laying a third steel mesh above the substrate, so that the arc boss structure is opposite to the Mini LEDs, and the third non-hole-forming area is aligned to a gap between two adjacent Mini LEDs in the row direction and the column direction; and in the laid third steel mesh, the first surface is the surface far away from the substrate. Pouring the packaging glue solution into a third cavity through a third opening to form corresponding packaging glue on each Mini LED; each Mini LED is packaged by independent packaging glue, and the packaging glue corresponding to two adjacent Mini LEDs is arranged at intervals in the row direction and the column direction; the top of the packaging adhesive is provided with an arc-shaped groove, and the side wall of the packaging adhesive is gradually close to the optical axis of the Mini LED corresponding to the packaging adhesive along the first direction; the first direction is perpendicular to the surface of the substrate and extends from the substrate to the direction of the Mini LED, and the side wall of the packaging adhesive refers to the area of the packaging adhesive except the top of the packaging adhesive and the bottom of the packaging adhesive; the top of the packaging adhesive refers to one side of the packaging adhesive, which is far away from the substrate layer, and the top of the packaging adhesive refers to one side of the packaging adhesive, which is close to the substrate.
In some embodiments, the Mini LEDs and the encapsulation glue corresponding to the Mini LEDs are arranged along the row direction and the column direction on the substrate surface. Obtaining a fourth steel mesh; the fourth steel mesh comprises a plurality of fourth perforated areas and a plurality of fourth non-perforated areas, each fourth perforated area is provided with a fourth cavity and a fourth opening for pouring grid glue solution into the fourth cavity, and the fourth non-perforated areas and the fourth perforated areas are alternately arranged in the row direction and the column direction; two fourth aperture regions adjacent in the row direction and two fourth aperture regions adjacent in the column direction are separated by a fourth non-aperture region. And laying a fourth steel mesh above the substrate, aligning the fourth perforated area to a gap between two adjacent packaging glues, and covering the area where the packaging glue is located by the fourth non-perforated area. Pouring the grid glue solution into the fourth cavity through the fourth opening of each fourth opening area to form a grid on the substrate; the grid is provided with a plurality of grids, the single packaging adhesive is surrounded by the grid wall body of the single grid, and a gap is formed between the grid wall body and the packaging adhesive. And performing light reflection treatment on the wall surface of the grid wall body facing the packaging adhesive.
It can be understood that the display device provided by the second aspect, the electronic apparatus provided by the third aspect, and the method for packaging the backlight module provided by the fourth aspect and the fifth aspect are associated with the backlight module provided by the first aspect, and therefore, the beneficial effects achieved by the method can refer to the beneficial effects in the backlight module provided by the first aspect, and are not repeated herein.
Drawings
FIG. 1 is a diagram illustrating the light propagation path of the light refraction phenomenon provided in an embodiment of the present application;
FIG. 2 is a diagram of an optical propagation path of the total reflection phenomenon provided in the embodiment of the present application;
FIG. 3 is a schematic structural diagram of a backlight module in a possible implementation manner;
fig. 4 is a comparison diagram of light action areas of the backlight module under different critical lines of total reflection according to the embodiment of the present application;
FIG. 5 is a schematic structural diagram of a backlight module in another possible implementation manner;
FIG. 6 is a schematic structural diagram of a backlight module in another possible implementation manner;
fig. 7 is a schematic structural diagram of a backlight module according to some embodiments of the present application;
FIG. 8 is a process diagram of the packaging process of the packaging adhesive of the backlight module shown in FIG. 7;
fig. 9 is a schematic partial structure view of a backlight module according to some embodiments of the present disclosure;
FIG. 10 is a diagram of an illumination model of an LED provided in an embodiment of the present application;
FIG. 11 is a comparison of two optical axis planes with the same uniformity of illumination provided by an embodiment of the present application;
fig. 12 is a schematic partial structure view of a backlight module according to another embodiment of the present application;
fig. 13 is a schematic partial structure view of a backlight module according to another embodiment of the present application;
fig. 14 is a schematic partial structure view of a backlight module according to another embodiment of the present application;
fig. 15 is a schematic partial structure view of a backlight module according to another embodiment of the present application;
fig. 16 is a schematic structural diagram of a backlight module according to another embodiment of the present application;
FIG. 17 isbase:Sub>A cross-sectional view of the backlight module shown in FIG. 16 taken alongbase:Sub>A sectional line A-A;
FIG. 18 is a process diagram of packaging the grid of the backlight module shown in FIG. 16;
fig. 19 is a schematic partial structure view of a backlight module according to another embodiment of the present application;
fig. 20 is a schematic structural diagram of a backlight module according to another embodiment of the present application;
fig. 21 is a schematic structural diagram of a backlight module according to another embodiment of the present application;
fig. 22 is a schematic structural view of a backlight module according to another embodiment of the present application;
fig. 23a is a schematic structural diagram of a backlight module according to another embodiment of the present application;
FIG. 23B is a schematic structural view of the backlight module shown in FIG. 23a cut along a cutting line B-B;
FIG. 24 is a comparison of light refraction for different configurations of encapsulant top portions according to embodiments of the present application;
FIG. 25 is a comparison of light refraction for different configurations of the sidewalls of the encapsulant, according to an embodiment of the present disclosure;
FIG. 26 is a process diagram of packaging the grid of the backlight module shown in FIG. 23 a;
fig. 27 is a schematic structural diagram of an electronic device according to an embodiment of the present application.
Detailed Description
First, technical terms related to embodiments of the present application are described.
(1) Encapsulation glue top, bottom and side walls
The top of the packaging adhesive refers to one side of the packaging adhesive, which is far away from the substrate; the bottom of the packaging adhesive refers to one side of the packaging adhesive close to the substrate; the area of the packaging adhesive except the top and the bottom of the packaging adhesive is the side wall of the packaging adhesive.
(2) Optically thinner medium and optically denser medium
For both media, the medium with the larger refractive index (in which light propagates at a slower rate) is called optically denser medium, and the medium with the smaller refractive index (in which light propagates at a faster rate) is called optically thinner medium.
It is understood that optically dense media is opposed to optically thinner media. For example, water is an optically dense medium with respect to air, but is an optically sparse medium with respect to glass.
(3) Angle of incidence and angle of refraction
The incident angle refers to the included angle between the incident light and the normal; the refraction angle refers to the angle between the refracted ray and the normal.
(4) The refraction of light refers to a phenomenon that when light obliquely enters another medium from one medium, the propagation direction is changed, so that the light is deflected at the interface of different media.
The deflection directions and angles of the light at the interfaces formed by different media are different. Illustratively, as shown in fig. 1 (a), when light is obliquely incident from the optically dense medium into the optically thinner medium, the refracted light ray is located between the imaginary line (i.e., the extension line of the incident light ray) and the interface, and is closer to the interface than to the normal, which means that the refracted light ray is deflected toward the direction in which the interface is located (or toward the direction away from the normal), and the incident angle θ Into Less than angle of refraction theta Folding device (ii) a As shown in fig. 1 (b), when light enters the optically denser medium from the optically thinner medium, the refracted light ray is located between the imaginary line (i.e., the extension of the incident light ray) and the normal line, and is closer to the normal line than the interface, which means that the refracted light ray is deflected in the direction of the normal line (or in the direction away from the interface), and the incident angle θ Into Greater than angle of refraction theta Folding device 。
(5) The reflection of light refers to the phenomenon that when light irradiates on the interface of two different media, the propagation direction is changed on the interface and the light returns to the original medium.
(6) Total reflection, also known as Total Internal Reflection (TIR), is a reflection phenomenon of light and occurs only when light enters a scene from an optically dense medium to an optically sparse medium. When light enters the light-dispersing medium from the optically dense medium, if the incident angle is larger than the critical angle of total reflection, the refracted light will disappear, and all the incident light will be reflected back to the optically dense medium without entering the light-dispersing medium, which is called the optical phenomenon as total reflection. Therefore, when the total reflection phenomenon occurs, the refraction phenomenon does not exist, and only the reflection phenomenon exists.
Illustratively, as shown in (a) of fig. 2, when an incident angle θ of an incident light ray is formed Into Less than critical angle of total reflection theta Face When the light is incident, refraction and reflection occur simultaneously; as shown in fig. 2 (b), as the incident angle θ is gradually increased Into When the light is refracted, the light is farther from the normal line and weaker (the thicker the line is, the stronger the light is represented; the thinner the line is, the weaker the light is represented), and the reflected light is stronger; as shown in (c) of fig. 2, when the incident angle θ Go into Greater than or equal to the critical angle of total reflection theta Face The refracted light will disappear and total reflection will occur.
In fig. 2, (c) is taken as an example, and the refractive index of the optically denser medium is assumed to be n 1 Refractive index of the optically thinner medium is n 2 Incident angle of theta 1 Angle of refraction θ 2 Then, the critical angle of total reflection θ Face ＝arcsin(n 2 /n 1 ). From critical angle of total reflection theta Face ＝arcsin(n 2 /n 1 ) It can be seen that n 1 The smaller, theta Face The larger; n is 2 The larger, theta Face The larger. That is, n is different between the optically thinner medium and the optically denser medium into which the light passes 1 And n 2 Will also differ, the critical angle of total reflection theta Face Also different. For convenience of illustration, in the embodiment of the present application, the critical angle θ of total reflection is defined as Medicine for treating 1 Representing the critical angle of total reflection, theta, of light incident into air from the side wall of the packaging adhesive Medicine 2 Representing the critical angle of total reflection, theta, of light incident on the diffusion layer (or diffusion plate) from the top of the packaging adhesive Medicine 3 Representing the critical angle of total reflection, theta, of light incident into air from the top of the packaging adhesive Medicine for curing cancer Representing the critical angle of total reflection of light incident into air from the diffusion layer, the critical angle of total reflection theta Face 5 Representing light raysThe critical angle of total reflection incident to the substrate from the bottom of the package glue.
At critical angle of total reflection theta Medicine for treating 1 For example, the critical angle θ of total reflection is exceeded Medicine for treating 1 The incident light refers to the light incident on the side wall of the packaging adhesive, and the incident angle is larger than or equal to the critical angle theta of total reflection Medicine for treating 1 Of the light source. Does not exceed the critical angle theta of total reflection Medicine for treating 1 The incident light is the light incident on the side wall of the packaging adhesive, and the incident angle is smaller than the critical angle theta of total reflection Medicine for treating 1 Of the light source. The incident light relative to other critical angles of total reflection can be referred to the critical angle of total reflection theta Medicine for treating 1 The incident light implementation is not described herein.
(7) Critical line of total reflection
In the embodiment of the present application, the critical line of total reflection refers to an incident light ray corresponding to the critical angle of total reflection. The included angle between the critical line of total reflection and the normal is the critical angle of total reflection.
(8) Halo effect
When a bright object is displayed, a bright or black aperture having a luminance difference from that of the bright object appears around the bright object.
The display panels available on the market are mainly classified into OLED and LCD. The OLED displays by utilizing the self-luminous characteristic of each pixel, and the LCD controls whether the backlight output by the backlight module passes or not by the deflection of the liquid crystal, for example, when pure white is displayed, the liquid crystal 'lets' all the backlight; while displaying pure black, the liquid crystal "shades" the backlight. Therefore, the display principles of the backlight module and the display module are completely different, the display effect of the LCD is slightly inferior to that of the OLED due to the difference, but the display quality of the LCD can be greatly improved by the backlight module with high brightness and high contrast, so that the LCD can be comparable to that of the OLED. Meanwhile, LCDs are lower in cost than OLEDs, and are therefore also used in large quantities in the market.
Generally, the LCD uses Mini LEDs as the light source of the backlight module. The Mini LED is an LED chip with the size of 100 μm, and the size of the Mini LED is between that of a small-pitch LED and that of a Micro LED, and is a result of further refinement of the small-pitch LED. The small-distance LED refers to an LED backlight source or a display product with the distance between adjacent lamp bead points being less than 2.5 millimeters. The Mini LED currently defined in the industry refers to an LED die with a size of 50-100 μm (micrometer), and an LED die with a size of 30 μm or less is called a Micro LED (also called a Micro light emitting diode). However, at present, the Mini LED (except for being listed separately, the Mini LED is referred to as LED for short in the following) is used as the backlight module of the backlight source, and the problems of low brightness, low contrast, halo effect and the like often occur, so that the display effect is poor, and the user experience is greatly reduced.
Referring to fig. 3, fig. 3 is a schematic structural diagram of a backlight module according to a possible design scheme. The backlight module comprises a substrate 1 and a plurality of LEDs 2 arranged on the substrate 1 in an array mode. It should be understood that fig. 3 illustrates only three LEDs 2, but this illustration should not be construed as a particular limitation on the number of LEDs 2.
For convenience of the following description, X is established on FIG. 3 1 Z 1 Coordinate system, X 1 The direction is the arrangement direction of the LEDs 2 and is parallel to the surface of the substrate 1, Z 1 The direction is perpendicular to the substrate plate surface and extends from the substrate plate surface toward the LEDs 2. It should be noted that if the LEDs 2 are arranged in a plurality of arrangement directions, X 1 The direction is any of a plurality of arrangement directions. For example, if the Mini LEDs are uniformly arranged on the substrate plate surface along the row direction and the column direction, then X 1 The direction is any one of a row direction and a column direction. For convenience of illustration, the backlight module shown in FIG. 3 has a line X 1 The first LED2 and the second LED2 in the direction are luminous LEDs along the X 1 The third LED2 of the direction is a non-emitting LED.
In order to realize light mixing, the backlight module adopts a whole piece of packaging adhesive 3 to cover a plurality of LEDs 2 together so as to package all the LEDs 2 in a whole surface manner. As can be seen from fig. 3, the encapsulation compound 3 covers not only the individual LEDs 2 themselves, but also the gaps between two LEDs 2. In order to enhance the display effect, a diffusion plate 41, a diffusion film 42, a brightness enhancement film 43, and a light conversion film 5 are further laminated on the sealing adhesive 3 in this order. The diffusion plate 41 and the diffusion film 42 diffuse light by fine particles on the optical film. The brightness enhancement film 43 reflects and refracts light by a micro-stripe (grating) structure formed on the optical film material, thereby redistributing the light. The light conversion film 5 converts the blue light emitted by the LED2 into red light, green light, blue light, and white light through the red quantum dots and the green quantum dots on the optical film material.
It should be noted that, referring to fig. 3, in some embodiments, the refractive indexes of the extended plate 41 and the substrate 1 are both smaller than the refractive index of the package adhesive 3. In this case, the monolithic structure of the encapsulant 3 would be equivalent to a waveguide, resulting in exceeding the critical angle θ of total reflection Medicine 2 And critical angle of total reflection theta Face 5 The incident light (i.e. the light with large angle output by the LED 2) is totally reflected and propagated in the structure of the packaging adhesive 3. Illustratively, ray A 1 Will be totally reflected at the interface M, passing through the light ray A 2 Reflecting to an interface N; light ray A 2 Totally reflecting at interface N, and passing through light A 3 Reflected to the interface M and then totally reflected at the interface M, so that the light is totally reflected between the interface M and the interface N in a reciprocating cycle, is constrained in the packaging adhesive 3, is totally reflected and transmitted, and is transmitted to the non-luminous LED2 (for example, along X) 1 The third LED 2) in the direction, the bright color of the area where the non-emitting LED2 is located is darker than that of the emitting LED2, thereby generating the halo effect.
In addition, in some embodiments, in order to improve the light mixing effect, the encapsulant 3 for the whole surface package is usually doped with more scattering particles, which makes the refractive index of the encapsulant 3 as an optical dense medium too large. According to the critical angle theta of total reflection Face ＝arcsin(n 2 /n 1 ) It can be seen that the refractive index n of the optically denser medium 1 Too large, will result in a critical angle of total reflection θ Face And decreases. The critical angle of total reflection is reduced, which will cause the halo effect to be more serious, and the specific analysis is as follows:
referring to fig. 4, fig. 4 is a comparison diagram of light action areas of the backlight module under different critical lines of total reflection. Ray B 1 、B 2 、B 3 Three distinct critical lines of total reflection. Critical line of total reflection B 1 Corresponding critical angle of total reflection<Critical line of total reflection B 2 Corresponding critical angle of total reflection<Critical line of total reflection B 3 Corresponding critical angle of total reflection. Wherein the critical line of total reflection B 1 、B 2 、B 3 The incident points at the division plane M are respectively b 1 、b 2 、b 3 . The incident points of the light rays A, C and D at the interface M are a, C and D respectively. It should be understood that the ray A is the beam center line of the LED2, and only the ray A is directed to X 1 The directionally extending regions illustrate the light active areas (i.e., the active areas of the diffuser plate 41 where backlight may be provided).
When the critical line for total reflection is located at B, as shown in FIG. 4 (a) 1 When the incident angle of the light ray A does not exceed the critical angle theta of total reflection Medicine 2 The light ray a will be transmitted at the interface M. The incident angles of the light rays C and D exceed the critical angle theta of total reflection Medicine 2 The light rays C, D will be totally reflected at the interface M and then obliquely directed to the position e at the interface N and the position f at the LED2, respectively.
As shown in fig. 4 (B), when the critical line of total reflection is located at B 2 When, unlike (a) in fig. 4, the incident angle of the light ray C does not exceed the critical angle θ of total reflection Medicine 2 And the incident angle of the light ray D exceeds the critical angle theta of total reflection Medicine 2 . On the basis of this, the light ray C will be refracted at the interface M, while the light ray D will be totally reflected at the interface M and then be obliquely directed to the position f at the LED 2.
When the critical line for total reflection is located at B, as shown in (c) of FIG. 4 3 In contrast to fig. 4 (b), the incident angles of the light rays C and D do not exceed the critical angle θ of total reflection Medicine 2 The rays C, D will be refracted at the interface M.
It should be understood that only the light transmitted through the diffuser plate 41 can provide an effective backlight and forms an effective area of the backlight (i.e., light action area) on the diffuser plate 41, while the light with total reflection is not transmitted through the diffuser plate 41 and cannot serve the purpose of backlight, and this light is lost to the backlight module. Based on this, in (a) in fig. 4, rays a to B 1 The light between is transmitted out of the diffuser plate 41, light B 1 Light rays emitted to the edge of the LED2 (hereinafter referred to as edge light rays) are totally reflected. Thus, the light-acting regions of the LED2 are a to b 1 . In fig. 4 (B), without considering the case of being blocked by the adjacent pixel points, the light rays a to B 2 The light between is transmitted out of the diffuser plate 41, light B 2 The light rays up to the edge rays are totally reflected, and thus the light action area of the LED2 is a to b 2 . In fig. 4 (c), without considering the case of being blocked by the adjacent pixel points, the light rays a to B 3 Is transmitted out of the diffuser plate 41, light B 3 The light rays to the edge are totally reflected, and thus the light action area of the LED2 is a to b 3 。
From the above, the critical angle of total reflection θ is closer to the normal line (i.e., the line where the light ray a is located) as the critical line of total reflection is closer to the normal line Medicine 2 The smaller the light output from the LED2, the less light will be transmitted through the diffuser plate 41 to be effectively used as a backlight, and the more light will be lost due to total reflection, so that the light action area of the LED2 is smaller, and the transmission ratio of light (the percentage of the light transmitted through the diffuser plate 41 to all the light emitted from the LED2, which may also be referred to as the extraction efficiency) will be lower. In short, the critical angle of total reflection θ Medicine 2 The reduction reduces the light emission efficiency and increases the total reflection phenomenon. It will be appreciated that, from the analysis of fig. 3, the halo effect is related to the phenomenon of total reflection of light rays, and becomes more severe as the phenomenon of total reflection increases. Therefore, in the backlight module shown in fig. 3, the package adhesive 3 doped with more scattering particles has a critical angle θ due to total reflection Medicine 2 Becoming smaller will exacerbate the halo effect described above.
It should be noted that fig. 3 illustrates a principle that the occurrence of total reflection may cause a halo effect, taking the package adhesive 3 as an optically dense medium and the diffuser plate 41 as an optically sparse medium as an example. It should be understood that, in other embodiments, as shown in fig. 5, the encapsulation adhesive 3 may also be an optically thinner medium, and the spreading plate 41 may also be an optically denser medium. In this case, although the light emitted from the LED2 is transmitted from the optically thinner medium to the optically denser medium without total reflection, the light with a large angle (for example, the light C) output from the edge region of the LED2 1 ) Possibly by refracting light rays at the interface M (e.g. rays C) 2 ) Refracted to the surrounding non-emitting LED2 (e.g. rim)X 1 The area directly opposite the third LED 2) is directly opposite the area of the extended plate 41, which also causes the area where the non-emitting LED2 is located to appear bright, thereby generating the halo effect.
In summary, the high-angle light output by the LED2 can "light up" the area where the surrounding non-light emitting LED2 is located by means of total reflection at the top of the encapsulation adhesive 3 and diffusion at the top of the encapsulation adhesive 3 into the area where the surrounding non-light emitting LED2 is located, thereby inducing a halo effect. It will be appreciated that the presence of the halo effect causes the area in which the non-emitting LED2 is located to be "lit" by the light output from the emitting LED2, thereby causing the emitting LED2 to emit light (e.g. along X) 1 The second LED2 in the direction) and the non-emitting LED2 (e.g. along X) 1 The third LED 2) in the direction cannot form a large contrast in the region, so that the backlight module has the problem of low contrast.
In addition, referring to fig. 3, the light in the central region of the led2 does not exceed the critical angle θ of total reflection Medicine 2 Refraction will occur at the interface M so that the transmitted light exits the diffuser plate 41 to provide backlighting. The light ray in the edge area of the LED2 exceeds the total reflection critical angle theta Medicine 2 The light is totally reflected and propagated at the interface M, and is confined in the package adhesive 3, and is not transmitted through the extending plate 41 and is lost. Therefore, the backlight module has high illuminance at the position facing the central area of the LED2, and has low illuminance at the position facing the edge area of the LED2, so that the backlight module has the problem of uneven illuminance. Referring to fig. 6, fig. 6 is a schematic structural diagram of a backlight module according to another possible implementation manner to solve the problem of uneven illuminance. Different from the backlight module shown in fig. 3, the light shielding structure 6 is further superimposed on the position of the encapsulation adhesive 3 facing the central area of the LED2 to shield and reflect light in the central area of the LED2 to weaken the illuminance in the central area of the LED2, so that the illuminance in the central area and the illuminance in the edge area of the LED2 are equivalent. However, the light shielding structure 6 will reduce the light emitting efficiency of the LED2, so that the bright spot (the area directly opposite to the LED2 emitting light, such as along X) of the backlight module 1 The area directly opposite the second LED2 in the direction) presents a problem of low brightness. And, a backlightThe bright spots of the module being not aligned with the dark spots (areas where the non-illuminated LED2 is aligned, e.g. along X) 1 The area directly opposite to the third LED2 in the direction) forms a larger contrast, which will aggravate the problem of low contrast of the backlight module.
In order to solve the problems of halo effect, low brightness, low contrast ratio and the like of the backlight module, the application provides an improved backlight module. The backlight module can be applied to a display device with a Mini LED2 as a backlight source, so that the display effect of the display device is improved, and the visual experience of a user is improved. The display device can be a device with an LCD display panel, such as a mobile phone, a tablet, a PC, a display, a white board, a large-screen terminal, an intelligent watch and the like, and the embodiment of the application has no special limitation on the specific form of the electronic equipment.
The backlight module provided in the embodiments of the present application will be described in detail with reference to fig. 7 to 25.
Referring to fig. 7, fig. 7 is a schematic structural diagram of a backlight module according to some embodiments of the present application. The backlight module comprises a substrate 1 and a plurality of LEDs 2 arrayed on the substrate 1. The LED2 is used as a light source of the backlight module and used for outputting light. The substrate 1 is used for laying metal traces that are used to electrically connect devices on the substrate 1, such as the LEDs 2, or other devices on the substrate 1. Alternatively, the routing on the substrate 1 may be implemented by etching or the like.
Different from fig. 3, in the backlight module shown in fig. 7, each LED2 is packaged with an independent packaging adhesive 3, and any two packaging adhesives 3 for packaging the LEDs 2 are arranged at intervals. Illustratively, along X 1 A space is kept between the first packaging adhesive 3 and the second packaging adhesive 3 in the direction. In some embodiments, in order to form the independent packaging adhesive 3 on the LED2, please refer to fig. 8, first, the steel net 7A (i.e. the first steel net) shown in (a) of fig. 8 is designed. As shown in fig. 8 (a), the steel net 7A includes open regions 71A and non-open regions 72A alternately arranged, in other words, the non-open regions 72A and the open regions 71A are arranged in a sequence of xyyx 8230; \8230; (X is the non-open region 72a and y is the open region 71A). Wherein the opening area 71A has a cavity (i.e. a first cavity) and can be filled with packaging adhesiveAn opening for the liquid (i.e., a first opening); two pairs of the open areas 71A are separated by a non-open area 72A. After obtaining the steel net 7A shown in fig. 8 (a), as shown in fig. 8 (b), the steel net 7A shown in fig. 8 (a) may be laid over the substrate 1 such that the open area 71A is aligned with the area where the LEDs 2 are located and the non-open area 72A is aligned with the gap between two LEDs 2. Then, the encapsulation glue is injected into the cavity, i.e., the hole site where the LED2 is located, from the opening of the open-cell area 71A by means of dispensing, spraying, brushing, and the like. Due to the existence of the non-perforated area 72A, the packaging glue solution can only be injected into the area where the LEDs 2 are located, and cannot be injected into the gap area between every two LEDs 2, so that the independent packaging glue 3 can be formed. And finally, curing is carried out, and independent packaging glue 3 is formed on the LED2, so that the LED2 is packaged.
Referring to fig. 7, to enhance the display effect, the upper edge Z of the packaging adhesive 3 1 The diffusion layer 4 and the light conversion film 5 are stacked in this order. Therefore, light output by the LED2 is transmitted by the corresponding packaging adhesive 3 and the diffusion layer 4 in sequence, enters the light conversion film 5, and is converted by the light conversion film 5 to output usable backlight. In some embodiments, the diffusion layer 4 may include a zone along Z 1 A diffusion plate 41, a diffusion film 42, and a brightness enhancement film 43 stacked in this order. In other embodiments, the diffuser layer 4 may include more or less optical films. For example, the diffusion layer 4 may include a zone along Z 1 A lower diffusion film, an upper diffusion film, a lower brightness enhancement film and an upper brightness enhancement film which are sequentially stacked in the direction; as another example, the diffusion layer 4 may also include a zone Z 1 The direction of the light filter film, the lower diffusion film, the upper diffusion film, and the brightness enhancement film stacked in this order, and the specific structure of the diffusion layer 4 is not particularly limited in the embodiments of the present application.
It should be noted that, the package glues 3 of two LEDs 2 are arranged at intervals, which means that the area between the sidewalls of two package glues 3 is air. Since the refractive index of the air is smaller than that of the packaging adhesive 3, when the high-angle light output by the LED2 enters the air from the side wall of the packaging adhesive 3, the light enters the optically denser medium to the optically thinner medium. In this case, there will be both the total reflection and refraction transmission of the light incident on the side wall of the package adhesive 3, which will be described below with reference to fig. 9 and 12 (fig. 9 and 12 are partially enlarged views of the region E1 in fig. 7).
In a first case, referring to fig. 9, to better show the propagation path of the light, compared to the area E1 in fig. 7, the light refracted at the top of the package adhesive 3 and the sidewall of the package adhesive 3 is omitted from fig. 9, and only the light totally reflected at the sidewall of the package adhesive 3 is remained.
As shown in fig. 9 (a), the critical angle of total reflection θ is exceeded Medicine for treating 1 Light ray A of 1 After reaching the side wall of the packaging adhesive 3, the full emission occurs, and light A passes through 2 Reflecting on top of the encapsulating glue 3. The dotted line with an arrow in the figure indicates the ray A 1 Directly from the packaging adhesive 3 to the diffusion layer 4 and through the light ray A after reaching the diffusion layer 4 3 The total reflection situation, i.e. the light ray A is illustrated when the packaging adhesive 3 has the structure shown in FIG. 3 1 The transmission path of (1). Visible, light ray A 1 In the structure shown in fig. 3 total reflection will occur at the top of the encapsulation glue 3.
Through comparison, the existence of air between the packaging glue 3 of every two LEDs 2 can be found, so that the light A which is originally emitted completely at the top of the packaging glue 3 can be obtained 1 The side wall of the encapsulated glue 3 is totally reflected to the top of the encapsulated glue 3, thereby reducing the light ray A 1 The halo effect due to the occurrence of total reflection, and the effective utilization of the light A 1 The illuminance above the LED2 is enhanced, and the light emission efficiency is improved.
In other embodiments, as shown in fig. 9 (b), the light ray a is different from fig. 9 (a) 1 The direct incidence of light from the encapsulation compound 3 into the diffusion layer 4 may not result in total emission, but rather through the light ray a 4 Refracts into the diffusion layer 4. It will be appreciated that ray A 4 There is a possibility of entering the area of the extended plate 41 directly opposite to the surrounding non-emitting LED2 (e.g. ray C in FIG. 5) 2 ). In this case, the presence of air between the encapsulating glue 3 of two LEDs 2 makes it possible to make the light ray a 1 Is totally reflected to the top of the packaging adhesive 3 by the side wall of the packaging adhesive 3 and approaches to the optical axis of the LED2, so as to avoid the light ray A 4 The possibility of entering the area of the extended plate 41 directly opposite to the surrounding non-luminous LED2 reduces the halo effect.
It should be noted that, in the backlight module, the ideal uniform illumination means that the minimum system thickness or the maximum LED2 pitch is used for the LED2 array on the premise that no perceptible non-uniform illumination occurs, so that the backlight module can be thinned and the number of LEDs 2 can be reduced on the premise that uniform illumination is ensured. The increase of the illuminance above the LED2 can make the height required for the illuminance to reach the illuminance uniformity of the specific specification smaller, so that the thinner the thickness of the backlight module is, the thinner the thickness of the display panel is, and the following detailed analysis is performed with reference to fig. 10 and 11.
The single LED2 is generally a generalized Lambertian light source with a light intensity distribution curve I θ ＝I o cos m Theta. Wherein, I o The intensity of the central ray of the LED2 (i.e., the ray along the optical axis); i is θ M is the intensity of light rays with an angle theta to the optical axis and can be measured by the half intensity angle theta of the LED2 1/2 And (5) determining. Referring to fig. 10, fig. 10 is a diagram of an illumination model of an LED according to an embodiment of the present disclosure. The optical axis refers to the center line of all the light rays emitted from the LED 2. The angle formed by the boundary lines of the region irradiated with the light is a beam angle when viewed from the optical axis plane perpendicular to the optical axis. The beam angle of the LED2 is generally defined as: light intensity I of the optical axis o 50% of (I) light intensity I o/2 Is irradiated on the area, and an included angle is formed by the boundary line of the area irradiated by the light. The half light intensity angle theta 1/2 Means that the light intensity is I o/2 The angle between the light ray and the optical axis. As can be seen from fig. 10, when θ = θ 1/2 When, I θ ＝I o/2 ＝0.5I o . Based thereon, according to I θ ＝I o cos m Theta is derived, m = -ln2/[ ln (cos theta) 1/2 )]. Visible, half intensity angle θ 1/2 The larger, the smaller m; half intensity angle theta 1/2 The smaller, the larger m. It should be noted that the more concentrated the light output from the LED2 is, the half-intensity angle θ 1/2 The smaller, the larger m; the more uniform the light output by the LED2, the half intensity angle theta 1/2 The larger, the smaller m.
Referring to fig. 11, fig. 11 is a comparison graph of two optical axis planes with the same illuminance uniformity according to an embodiment of the present application. For convenience hereinafterDescribed, taking as an example a rectangular parallelepiped in which the shape of the LED2 shown in fig. 11 is flat (wide flat and thin structure), O — X is established on the LED2 shown in fig. 11 2 Y 2 Z 2 A coordinate system. Wherein the origin O is at the geometric center of the LED2, X 2 Y 2 The surface being perpendicular to the optical axis of the LED2, Z 2 Oriented parallel to the optical axis of the LED2, X 2 The direction is parallel to the long side of the LED2 board surface, Y 2 The direction is parallel to the short side of the plate surface of the LED 2. The flat cuboid resembles a "plate" and thus has a plate surface. The plate surface of the LED2 is a surface perpendicular to the optical axis of the LED 2. It is understood that X 2 Direction, Y 2 The directions may be parallel to the short side and the long side of the surface of the LED 2. It will also be appreciated that in other embodiments the shape of the LED2 may be other shapes, for example a cylinder with a circular face, in which case X 2 Direction and Y 2 The directions are vertical and all extend along the circular radial direction. As another example, the plate surface is a rectangular parallelepiped, in which case X 2 Direction, Y 2 The directions respectively extend along one adjacent side of the square, which is not specifically limited in this embodiment of the present application.
The illuminance distribution at any point (x, y, z) on the optical axis plane is
Figure GDA0004002627810000111
Wherein L is LED2 at X 2 The length of the direction; w is LED2 at Y 2 The width of the direction; h is LED2 at Z 2 The height of the direction; x is the point on the optical axis plane and the O point of the LED2 in X 2 The distance in the direction, Y is the distance between the point on the optical axis plane and the point O of the LED2 in the direction of Y 2 The distance in the direction Z is the distance between the point on the optical axis plane and the point O of the LED2 in the direction Z 2 The pitch of the directions. Referring to fig. 11, optical axis plane a and optical axis plane B are two optical axis planes with the same illumination uniformity. It should be noted that illuminance uniformity refers to the ratio of the minimum illuminance to the average illuminance on the illuminated surface. The more uniform the light distribution, the higher the uniformity of the illumination, and the closer the illumination E (x, y, z) across the optical axis plane. As can be seen by comparing (a) and (B) in FIG. 11, the same LEDs 2 reach on the optical axis plane A and the optical axis plane B, respectivelyThe same illuminance uniformity, half-intensity angle θ of LED2 shown in (a) of FIG. 11 1/2 Larger than half light intensity angle theta of LED2 shown in (b) of FIG. 11 1/2 That is, m of the LED2 shown in FIG. 11 (a) is smaller than m of the LED2 shown in FIG. 11 (b), but each point on the optical axis plane A and the point O are at Z 2 The spacing in the direction (i.e. Z) is greater than the Z distance between each point on the optical axis plane B and the point O 2 The smaller the m, the smaller the required height z, the more uniform the directional spacing, i.e. the illumination of the individual LEDs 2 on the optical axis plane, achieves the same illumination uniformity.
In summary, in the backlight module shown in fig. 7, when the illuminance above the LED2 is increased, it means that the stronger the luminous flux above the LED2 is, the higher the light density is, and the more uniform the illuminance above the LED2 is. From the analysis of FIG. 10, it can be seen that the more concentrated the light output from LED2, the more the half intensity angle θ 1/2 The smaller, the larger m; the more uniform the light output by the LED2, the half intensity angle theta 1/2 The larger, the smaller m. Therefore, in the backlight module shown in FIG. 7, the more the uniformity of the illumination over the LEDs 2 is, the half-intensity angle θ 1/2 The larger m. As can be seen from the analysis of fig. 11, the smaller m, the smaller z required by the LED2 to achieve a particular specification of uniformity of illumination. For the backlight module shown in FIG. 7, the optical axis plane and Z of the LED2 1 The direction (i.e. the thickness direction of the backlight module) is vertical, and z is the distance between each point on the optical axis plane and the geometric center of the LED2 in the thickness direction of the backlight module, so in the backlight module shown in fig. 7, the smaller m is, the smaller z is required in the thickness direction of the backlight module for achieving the illumination uniformity of the LED2 to reach the specific specification, and therefore, the thinner the thickness of the backlight module is, the thinner the thickness of the display device is.
In the second case, referring to fig. 12, to better show the propagation path of the light, compared to the area E1 in fig. 7, the light refracted at the top of the encapsulant 3 and the light totally reflected at the sidewall of the encapsulant 3 are omitted from fig. 12, and only the light refracted at the sidewall of the encapsulant 3 is remained.
As shown in fig. 12 (a), the critical angle of total reflection θ is not exceeded Medicine for treating 1 Light ray B of 1 After the light enters the side wall of the packaging adhesive 3, refraction occurs at the interface between the side wall of the packaging adhesive 3 and air,and passes through the light ray B 2 To the diffusion layer 4. Due to the light ray B 2 Since air having a small refractive index is incident on the diffusion layer 4 having a large refractive index, the light ray B 2 Passes through the light B after reaching the diffusion layer 4 3 Refracted into the diffusion layer 4. The dotted line with arrows in the figure indicates the ray B 1 Directly enters the diffusion layer 4 from the packaging adhesive 3 without being refracted by air, and passes through the light ray B after reaching the diffusion layer 4 4 The total reflection situation, i.e. the light ray B when the packaging adhesive 3 has the structure shown in FIG. 3 1 The transmission path of (2). Visible light ray B 1 Total reflection will occur in the structure shown in fig. 3.
By contrast, it can be seen that the same is ray B 1 In the structure of the package paste 3 shown in fig. 7, transmission (i.e., refraction) occurs, and in the structure of the package paste 3 shown in fig. 3, a total reflection phenomenon occurs. That is, compared to the backlight module shown in fig. 3, the interval arrangement of the encapsulant 3 can reduce the occurrence of the total reflection phenomenon. Since the total reflection phenomenon in fig. 3 may cause light to propagate in the package adhesive 3 in a total reflection manner, thereby generating a halo effect, the halo effect may be reduced by reducing the total reflection phenomenon in fig. 7.
As shown in fig. 12 (b), ray C 1 After the light is incident to the side wall of the packaging adhesive 3, the light is refracted at the interface between the side wall of the packaging adhesive 3 and the air and passes through the light ray C 2 Is transmitted to the diffusion layer 4 due to the light C 2 Since the light ray C is incident from the air having a small refractive index to the diffusion layer 4 having a large refractive index 2 Passes through the light C after reaching the diffusion layer 4 3 Refracted into the diffusion layer 4. The dotted line with arrows in the figure indicates the light ray C 1 Is not refracted by air, but directly enters the diffusion layer 4 from the packaging adhesive 3, and passes through the light C after reaching the diffusion layer 4 4 Into the diffusion layer 4, i.e. the light C is shown when the packaging adhesive 3 has the structure shown in FIG. 3 1 The transmission path of (1).
By comparison, it can be found that the same light C 1 Light C refracted through air 3 Relative to light C not refracted by air 4 More toward Z 1 And (4) direction. That is to say that the temperature of the molten steel is,the presence of air alters the light C 1 The large-angle light rays output from the edge area of the LED2 are converged more toward the center and reach the position a of the diffusion layer 4, and are closer to the emitted light ray C than the position b which reaches the diffusion layer 4 without being refracted by air 1 And further away from other surrounding LEDs 2, so that light C can be avoided 1 The light enters the area of the extended plate 41 opposite to the non-luminous LED2 around, so that the area where the non-luminous LED2 is located appears bright, and further, the halo effect can be reduced.
In summary, in the backlight module shown in fig. 7, the encapsulation adhesives 3 of two LEDs 2 are disposed at intervals, and air is filled between the encapsulation adhesives 3 of two LEDs 2. The light reaching the side wall of the packaging adhesive 3 is transmitted from the packaging adhesive 3 as an optically dense medium to the air as an optically sparse medium, so that the light which is totally reflected at the top of the packaging adhesive 3 or is diffused into the area where the peripheral non-luminous LED2 is positioned to cause a halo effect can be totally reflected at the side wall of the packaging adhesive 3 or transmitted to the Z direction 1 The direction deflection mode is close to the optical axis of the LED2 and refracts the light into the diffusion layer 4, so that the illuminance above the LED2 can be enhanced, the emergent efficiency is improved, and the halo effect is reduced.
In the backlight module shown in fig. 7, the side wall of the packaging adhesive 3 is totally reflected or directed to Z 1 After entering the diffusion layer 4, the light rays in the form of directional deflection are either refracted through the diffusion layer 4 into the light conversion film 5 to provide backlight, or are totally reflected at the top of the diffusion layer 4 (the side of the diffusion layer 4 away from the substrate). Specifically, in the backlight module shown in fig. 7, the encapsulating adhesives 3 of two LEDs 2 are arranged at intervals, so that the upper side (the side of the diffusion layer 4 away from the substrate 1) and the lower side (the side of the diffusion layer 4 close to the substrate 1) of the region where the diffusion layer 4 is located between two encapsulating adhesives 3 are both air, and the diffusion layer 4 in the region becomes a waveguide. Based on this, fig. 7 shows the light B originally totally reflected at the top of the package adhesive 3 shown in fig. 3 1 Light ray C 1 After being refracted into the diffusion layer 4, if the light B is 1 Light ray C 1 Does not exceed the critical angle theta of total reflection Face 4 Will be transmitted out through the diffusion layer 4, thereby improving the light extraction efficiency and reducing the lightThe total reflection phenomenon is reduced to reduce the halo effect. If the light ray B 1 Light ray C 1 Exceeding critical angle theta of total reflection Face 4 The total internal reflection propagation of the diffusion layer 4 between every two packaging glues 3 can also reduce the halo effect for the latter, and the specific analysis is as follows:
referring to FIG. 3, ray B 1 Light ray C 1 Totally reflecting at the positions a and B of the boundary surface M, respectively, and passing through the light rays B 2 Light ray C 3 Reflected to the boundary surface N, it can be seen that the incident angles of the light rays from the first LED2 and the second LED2 to the position a to the position b in FIG. 3 are all larger than the critical angle θ of total reflection Medicine 2 Therefore, no light will be transmitted from position a to position b, and a darker aperture will be present, resulting in a halo effect, and especially when the distance from position a to position b is larger, a distinct black ring will appear, and the halo effect is more pronounced. The backlight module shown in fig. 7 refracts the light into the diffusion layer 4, and then diffuses outward layer by layer through the diffusion layer 4 until reaching the top of the diffusion layer 4, and then totally reflects the light. Therefore, the light rays diffused outwards layer by layer through the diffusion layer 4 are far away from the optical axis of the LED2 at the position where the light rays are totally reflected after reaching the top of the diffusion layer 4, and the positions where the light rays output by every two LEDs 2 are totally reflected at the top of the diffusion layer 4 are closer, so that the distance of a wireless transmission area can be reduced, and the halo effect is reduced.
Referring to fig. 7, in some embodiments, in order to reduce the halo effect and improve the light emitting efficiency, the diffusion layer 4 and the encapsulant 3 are disposed in a lamination manner, such that the diffusion layer 4 and the encapsulant 3 are in close contact with each other, and the refractive index of the diffusion layer 4 is greater than the refractive index of the encapsulant 3.
It should be noted that, because the diffusion layer 4 and the package adhesive 3 are in close contact, a zero optical distance is maintained between the diffusion layer 4 and the package adhesive 3, and no air exists, so that light incident on the top of the package adhesive 3 directly enters the diffusion layer 4. It will be appreciated that when there is an optical distance between the diffuser layer 4 and the encapsulant 3, light incident on the top of the encapsulant 3 is first refracted into the air and then into the diffuser layer 4 through the air. Since the refractive index of the diffusion layer 4 is larger than that of the diffusion layerThe refractive index of air, and therefore, light entering the diffusion layer 4 directly from the top of the encapsulant 3 is closer to Z than light entering air 1 The direction makes the light output from the top of the packaging adhesive 3 more convergent and more distant from other surrounding LEDs 2, and the halo effect caused by the light diffused into the surrounding areas of other LEDs 2 at the top of the packaging adhesive is less likely to occur.
In addition, since the refractive index of the diffusion layer 4 is greater than that of the encapsulant 3, the encapsulant 3 is an optically thinner medium, and the diffusion layer 4 is an optically denser medium. According to the definition of total reflection, the light is totally reflected when the light is incident from the optically dense medium to the optically sparse medium, and the light is not totally reflected when the light is incident from the optically sparse medium to the optically dense medium. Based on this, the light with a large incident angle incident on the top of the packaging adhesive 3 will not be totally reflected, but is totally refracted out through the diffusion layer 4, thereby increasing the transmission ratio (i.e. the outgoing efficiency) of the light and reducing the occurrence of the total emission phenomenon. Compared with the backlight module shown in fig. 3, the embodiment is beneficial to reducing the halo effect caused by the total reflection phenomenon of the large-angle light rays on the top of the packaging adhesive 3. Moreover, since the light is incident from the encapsulant 3 as the optically thinner medium to the diffusion layer 4 as the optically denser medium, the exit angle of the light output from the top of the encapsulant 3 can be reduced, in other words, the light output from the top of the encapsulant 3 to the diffusion layer 4 will be directed to Z 1 Deflected in direction to converge, rather than in X direction 1 The direction is diffused, so that the halo effect caused by the diffusion of the high-angle light to the surrounding area where the non-luminous LED2 is located can be relieved.
Fig. 7 illustrates the influence of the zero-optical-distance structure on light transmission, taking as an example that the refractive index of the diffusion layer 4 is larger than that of the encapsulant 3. It is to be understood that in other embodiments, the refractive index of the diffusion layer 4 may also be smaller than the encapsulant 3 when the diffusion layer 4 and the encapsulant 3 are in intimate contact. Since the zero optical distance is kept between the diffusion layer 4 and the packaging adhesive 3, no air exists, and the light output from the LED2 to the top of the packaging adhesive 3 is also directly incident to the diffusion layer 4 from the packaging adhesive 3. Although the light refracted into the diffusion layer 4 is further away from Z than in fig. 7 1 And (4) direction. But the light output from the top of the encapsulant 3 is directed more towards Z than in the case of an optical distance solution 1 The directional deflection causes the light to be more concentrated, which also reduces the halo effect described above, as will be discussed in more detail below with reference to fig. 13.
Referring to fig. 13, (a) and (b) in fig. 13 respectively illustrate the influence of the optical distance between the diffusion layer 4 and the encapsulant 3 on the light propagation. It will be appreciated that since the refractive index of the diffusion layer 4 is greater than that of air, θ is compared to the critical angle of total reflection Medicine 2 Corresponding critical line of total reflection B 2 Critical angle of total reflection theta Medicine 3 Corresponding critical line of total reflection B 3 More towards Z 1 And (4) direction.
As shown in fig. 13 (a), this figure shows a diagram of a propagation path of light when no air exists between the diffusion layer 4 and the encapsulating adhesive 3. In this case, the critical angle θ of total reflection is not exceeded in the light incident on the top of the encapsulant 3 Medicine 2 Ray A of 1 Ray A 2 Ray A 3 Refracting from the top of the packaging adhesive 3 into the diffusion layer 4 at the positions a, b and c of the diffusion layer 4 respectively; while exceeding the critical angle theta of total reflection Medicine 2 Ray A of 4 Total reflection will occur causing loss of this portion of the light. As shown in fig. 13 (b), this figure shows a diagram of a propagation path of light in the presence of air between the diffusion layer 4 and the encapsulating adhesive 3. In this case, the critical angle θ of total reflection is not exceeded in the light incident on the top of the encapsulant 3 Medicine for treating arthritis 3 Light ray A of 1 Will refract into the air, and refract to the position d of the diffusion layer 4 through the air separately; and exceeds the critical angle theta of total reflection Medicine 3 Light ray A of 2 Ray A 3 Total reflection will occur causing loss of this portion of the light.
Comparing the two figures, it can be seen that the presence of air between the diffusion layer 4 and the encapsulant 3 will cause total reflection of more light rays (such as the light ray A2), thereby reducing the light extraction efficiency. On the contrary, no air exists between the diffusion layer 4 and the packaging adhesive 3, so that the total reflection light (such as the light A2) is reduced, and the light emitting efficiency is improved. It should be understood that, compared to the backlight module shown in FIG. 3, the backlight module is fully invertedThe reduction of the radiation phenomenon is beneficial to reducing the halo effect caused by the total reflection phenomenon of the large-angle light on the top of the packaging glue 3. In addition, it can be seen by comparison that the same is ray A 2 The position d reaching the diffusion layer 4 after air refraction is farther from the position a where the optical axis reaches the diffusion layer 4 than the position b reaching the diffusion layer 4 without air refraction. That is, air exists between the diffusion layer 4 and the encapsulant 3, so that light output from the top of the encapsulant 3 is directed away from the package Z 1 The direction deflects, and the light output from the top of the packaging adhesive 3 is more dispersed and closer to other non-luminous LEDs 2 around, so that the light is easily emitted into the area of the expansion plate 41 opposite to the non-luminous LEDs 2 around, the area where the non-luminous LEDs 2 are located is bright, and the halo effect is generated. On the contrary, no air exists between the diffusion layer 4 and the packaging adhesive 3, so that the light rays can be enabled to be in the Z direction 1 The direction deflects, so that the light output from the top of the packaging adhesive 3 is more converged and is further away from other surrounding LEDs 2, and the halo effect is less likely to be generated.
In summary, no matter whether the refractive index of the encapsulant 3 is smaller than the refractive index of the diffusion layer 4 or not, the diffusion layer 4 and the encapsulant 3 are attached to each other in fig. 7, and the scheme without optical distance can enable the light output from the top of the encapsulant 3 to be directed to the Z direction compared with the scheme with optical distance between the diffusion layer 4 and the encapsulant 3 1 The direction is deflected to reduce the halo effect.
It is understood that when the refractive index of the encapsulation paste 3 is greater than that of the diffusion layer 4, total reflection of light incident to the diffusion layer 4 from the top of the encapsulation paste 3 may occur, thereby reducing the light extraction efficiency. In this case, in order to reduce the occurrence of the phenomenon of total emission from the top of the encapsulant 3, it is desirable to make the incident angle of the light incident on the top of the encapsulant 3 not more than the critical angle θ of total reflection Medicine 2 So that the light incident on the top of the packaging adhesive 3 is not totally reflected. Based on this, in some embodiments, in order to make the light incident on the top of the packaging adhesive 3 not totally reflected as much as possible, a detailed description of how to set the width of the packaging adhesive 3 is given below with reference to fig. 14 and 15.
Please continue to refer to FIG. 14Fig. 14 is a schematic partial structure view of a backlight module according to another embodiment of the present application. Fig. 14 (a) and (b) show two different widths of the potting adhesive 3. As shown in fig. 14 (a) and (b), the encapsulating adhesive 3 in fig. 14 (b) is at X 1 The width in the direction is wider, and the packaging adhesive 3 is in X in (a) in FIG. 14 1 The width of the direction is narrower. In fig. 14, (a) and (b) are the same except that the width of the sealing adhesive 3 is different, for example, the refractive index of the sealing adhesive 3, the refractive index of the diffusion layer 4, and parameters of the LED 2. Therefore, (a) in fig. 14 and (b) in fig. 14 have the same critical angle θ of total reflection Medicine 2 And a corresponding total reflection boundary line B 2 。
As can be seen from (a) and (b) in fig. 14, when the packaging adhesive 3 is at X 1 Width in direction greater than that of LED2 in X 1 When the width of the direction is wide, the light output by the LED2 obliquely enters the top of the packaging adhesive 3, so that the possibility of total reflection exists. When the packaging adhesive 3 is at X, as shown in FIG. 14 (a) 1 Wide in direction, so that the critical line B of total reflection 2 The position reaching the top of the packaging adhesive 3 is not on the top edge line of the packaging adhesive 3, so the edge region E2 on the top of the packaging adhesive 3 will have light (such as light a) 1 Light ray A 2 ) Incident angle of the part of light is larger than total reflection critical angle theta Medicine 2 So that total reflection occurs at the top of the encapsulation paste 3. Wherein the edge region E2 is a critical line B for total reflection 2 Reaching the area between the position a at the top of the encapsulating glue 3 and the edge line at the top of the encapsulating glue 3. When the packaging adhesive 3 is at X, as shown in FIG. 14 (b) 1 The width of the direction is narrow, so that the total reflection critical line B 2 The position of the top of the encapsulating glue 3 is on the top edge line of the encapsulating glue 3, so that the top of the encapsulating glue 3 is not only along the critical line B for total reflection 2 The incident angles of other light rays reaching the top of the packaging adhesive 3 outside the transmitted light rays are all smaller than the critical angle theta of total reflection Medicine 2 So that the top of the packaging adhesive 3 is not totally reflected. Based on this, without changing the critical line B of total reflection 2 In this case, the sealing adhesive 3 may be applied at X 1 The width of the direction is less than the critical line B of total reflection 2 To the position of the diffusion layer 4a, to reduce the occurrence of total reflection phenomenon on the top of the packaging adhesive 3.
Referring to fig. 15, fig. 15 is a schematic partial structure view of a backlight module according to another embodiment of the present application. In fig. 15 (a) and (b), the sealing adhesive 3 is at X 1 The width of the direction is just at the critical line B of total reflection 2 To the position of the diffusion layer 4. The difference is that in (a) in fig. 15, the critical line B for total reflection 2 Output from a region within the edge line of the LED2, and a total reflection boundary line B in FIG. 15 (B) 2 Output by the edge lines of the LEDs 2. By comparison, it can be found that the critical line B for total reflection in (B) of fig. 15 2 When the light is output from the edge line of the LED2, most of the light is smaller than the critical angle theta of total reflection Medicine 2 Therefore, most of the light will be transmitted from the top of the packaging adhesive 3, and there is substantially no light a emitted from the side wall of the packaging adhesive 3 in fig. 15 (a) 1 And a ray A 2 . It should be understood that although the light ray A is emitted from the side wall of the package adhesive 3 1 And a ray A 2 Can be directed to Z 1 The direction is deflected, but it is not excluded that it is lost by total reflection propagation within the diffusion layer 4, or still hits the surrounding area where the non-emitting LED2 is located. Therefore, the critical line B of total reflection shown in fig. 15 (B) is used 2 Setting the packaging adhesive 3 at X 1 The width of the direction can have higher light-emitting efficiency.
Based on this, as shown in (b) of fig. 15, the package adhesive 3 is applied at X 1 The width of the direction is just at the critical line B of total reflection 2 The position of incidence to the diffusion layer 4 is taken as an example, and the packaging adhesive 3 is arranged at X 1 Width L of direction 2 From LED2 at X 1 Width L of direction 1 And two packaging glues 3 are in X 1 Single side width L of direction widening LED2 3 The three parts are formed. Thus, L 2 ＝L 1 +2L 3 ＝L 1 +2L 3 ＝L 1 +2h*tanθ Medicine 2 ＝L 1 +2h*tan(arcsin(n 2 /n 1 ). Wherein, theta Medicine 2 The critical angle of total reflection, n, of light incident on the diffusion layer 4 from the top of the packaging adhesive 3 2 Is the refractive index of the diffusion layer 4, n 1 Is the refractive index of the packaging adhesive 3, h is the packageGlue 3 in Z 1 The direction is higher than the height of the LED2, and the LED2 is arranged at Z 1 When the thickness in the direction is ignored, h can be regarded as that the packaging adhesive 3 is in Z 1 The thickness in the direction. It should be understood that in (B) in fig. 15, when following the critical line B for total reflection 2 When the transmitted light reaches the top of the packaging adhesive 3, the light is just totally reflected, so that L is used for avoiding the occurrence of total reflection phenomenon as much as possible 2 ＜L 1 +2h*tan(arcsin(n 2 /n 1 )。
It should be noted that, in the backlight module shown in fig. 7, with the reduction of the halo effect, the area where the peripheral non-light-emitting LED2 is located is not easily "lighted" by the light output by the light-emitting LED2, so that a large contrast can be formed between the area where the light-emitting LED2 is located and the area where the non-light-emitting LED2 is located, thereby forming a high contrast ratio. In addition, because the shading structure shown in fig. 6 is not arranged, the condition of lower brightness can not occur, and the side wall of the packaging adhesive 3 totally reflects the large-angle light output from the edge of the LED2 to the top of the packaging adhesive 3, so that the light gathering is favorably increased, and the brightness can be further improved.
It should be understood that, although the backlight module shown in fig. 7 is provided with the diffusion layer 4 and the packaging adhesive 3 in close contact, the light output from the LED2 can be directly refracted to the diffusion layer 4 from the top of the packaging adhesive 3. However, the light refracted into the diffusion layer 4 is directed more towards Z than in the case of an optical distance solution 1 The direction is deflected, so that the light rays approach the center, and the edge illuminance of the packaging adhesive 3 is weaker, and the better illumination uniformity cannot be achieved.
Referring to fig. 16, fig. 16 is a schematic structural diagram of a backlight module according to another embodiment of the present application. Unlike the backlight module shown in fig. 7, in the backlight module shown in fig. 16, the diffusion layer 4 and the encapsulation adhesive 3 are disposed at an interval such that air exists between the diffusion layer 4 and the encapsulation adhesive 3, and an optical distance exists between the diffusion layer and the encapsulation adhesive 3. In order to provide an optical distance between the diffusion layer 4 and the encapsulant 3, in some embodiments, the backlight module shown in fig. 7 can be arranged along Z 1 Diffusion plate 41, diffusion film 42, and light-intensifying element sequentially laminated in the directionThe film 43 is a three-layer film material, and is replaced by a synthetic film material with only one layer, and the synthetic film material has all the effects of the three film materials of the diffusion plate 41, the diffusion film 42 and the brightness enhancement film 43. Thus, the backlight module is not increased along the Z direction 1 In the case of directional thickness, the diffusion layer 4 may be raised in such a way that the thickness of the diffusion layer 4 is reduced, so that there is an optical distance between the diffusion layer 4 and the encapsulation adhesive 3. In other embodiments, the diffusion layer 4 may also be raised by increasing the thickness of the backlight module, so as to obtain an optical distance, which is not specifically limited in the embodiments of the present application.
It will be appreciated that when air is present between the diffuser layer 4 and the encapsulant 3, light is refracted into the air (optically thinner medium) from the top of the encapsulant 3 (optically denser medium) first, with the refracted light deviating from Z 1 In a direction, i.e. towards X 1 Deflected in direction and then re-injected into the diffusion layer 4. Compared with the scheme of fig. 7 in which light is directly injected into the diffusion layer 4 from the top of the encapsulation adhesive 3, the refraction of air can make the light far away from Z 1 The direction deflects for the light of 3 top outputs of packaging glue is toward outer diffusion, thereby reaches better illuminance uniformity, and LED2 reaches the required backlight unit's of the illuminance uniformity of specific specification thickness thinner, thinner display device's thickness. But at the same time the presence of air causes the light reaching the top of the encapsulation glue 3 to be directed X-wise 1 The direction is deflected, so that total reflection is more likely to occur or the light enters a region where the surrounding non-luminous LED2 is located, and a halo effect is caused, and specific analysis may refer to relevant contents shown in fig. 7 and fig. 13, which is not described herein again. Based on this, in order to suppress the generation of the halo effect while ensuring the uniformity of the backlight unit, as shown in fig. 16, a grid 8 is further connected between the diffusion layer 4 and the substrate 1. The grid 8 has a plurality of grids 83, and the grid walls 84 of all the grids 83 constitute the grid 8.
Specifically, referring to fig. 17, fig. 17 isbase:Sub>A cross-sectional view of the backlight module shown in fig. 16, which is cut alongbase:Sub>A cutting linebase:Sub>A-base:Sub>A. For convenience of the following description, X is established on FIG. 17 1 Y 1 Coordinate system, X 1 Y 1 In a plane parallel to the substrate 1, and Z 1 Direction of vertical, X 1 One of the direction and the arrangement direction of the LEDs 2In, e.g. the row direction, Y 1 The direction is the other, e.g. column, direction of the LEDs 2. As shown in FIG. 17, the grid 8 includes a rim X 1 A plurality of transverse bars 81 distributed in the direction and along Y 1 A plurality of longitudinal bars 82 distributed in the direction. The transverse bars 81 and the longitudinal bars 82 are criss-crossed to form a plurality of grids 83. The individual potting compound 3 is surrounded by a grid wall 84 of the individual grid 83. It can be seen that in X 1 Two packaging glues 3 adjacent to each other in the direction, such as the packaging glue 31 (i.e., the first packaging glue) and the packaging glue 32 (i.e., the second packaging glue), are separated by the grid wall 84 (i.e., the spacer unit). The wall surface of the grid wall 84 facing the first package adhesive 3 (i.e., the first plate surface) and the wall surface of the grid side wall 84 facing the first package adhesive 3 (i.e., the second plate surface) have a light reflection function.
In some embodiments, referring to fig. 18, in order to form the grating 8, first, the steel net 7B shown in (a) of fig. 18 is designed. As shown in fig. 18 (a), the steel net 7B (i.e., the second steel net or the fourth steel net) includes open areas 71B and non-open areas 72B alternately arranged, in other words, the non-open areas 72B and the open areas 71B are arranged in a sort order of xyxyyx (X is the non-open area 72b, and y is the open area 71B). Wherein, the open-cell area 71B is provided with a cavity (namely, a second cavity or a fourth cavity) and an opening (namely, a second opening or a fourth opening) for pouring grid glue into the cavity; the non-opening area 72B has a cavity for accommodating the packaging adhesive 3, and every two opening areas 71B are separated by the non-opening area 72B. After obtaining the steel net 7B shown in fig. 18 (a), as shown in fig. 18 (B), after the encapsulation of the LED2 is completed, secondary steel net printing is performed by laying the steel net 7B shown in fig. 18 (a) over the substrate 1 so that the open areas 71B are aligned with the gaps between two pieces of the encapsulation paste 3 and the non-open areas 72B cover the areas where the encapsulation paste 3 is located. After the packaging of the LED2 is completed, a steel mesh 7B with an open area 71B and a non-open area 72B is used for secondary steel mesh printing, so that the open area 71B is aligned with the gap between every two packaging glues 3, and the non-open area 72B covers the area where the packaging glues 3 are located. Next, the grid glue solution is injected from the open-cell area 71B by dispensing, spraying, brushing, etc., so as to form grid bars on both sides of the package glue 3, thereby forming the grid wall 84. And then cured to form a grid 8 on both sides of the encapsulation glue 3. Finally, a reflective coating may be formed on the grid wall 84 by sputtering, spraying, or the like, or a reflective paper, a reflective film, or the like may be directly attached to the grid wall 84, so that the grid wall 84 has a light reflection function, and it is ensured that light rays between adjacent grids 83 do not cross each other. In other embodiments, the grid 8 with the above structure can be manufactured by injection molding, stamping, or other forming methods.
The following is a detailed analysis of how the grid ensures the uniformity of the backlight module and suppresses the generation of the halo effect in conjunction with fig. 19.
Referring to fig. 19, fig. 19 is a partially enlarged view of a region E3 in fig. 16. Due to the presence of air between the diffusion layer 4 and the encapsulation glue 3, the light ray A reaching the top of the encapsulation glue 3 1 By means of a light ray A 2 To X 1 The light beam A is deflected to be closer to the area where the non-emitting LED2 is located, assuming that there is no grid wall 84 (the backlight module shown in FIG. 7) 2 Will enter the area where the surrounding non-emitting LED2 is located, causing a halo effect. In the backlight module shown in FIG. 19, the existence of the grid wall 84 changes the light A 2 In the direction of propagation of the light ray A 3 To the area of the extended plate 41 above the LEDs 2, thereby preventing this light from entering the surrounding area where the non-emitting LEDs 2 are located, and thus reducing the halo effect. In addition, since the optical distance is kept between the diffusion layer 4 and the packaging adhesive 3, the backlight module shown in fig. 16 can move the light output by the LED2 away from Z 1 The direction is deflected, so that the illuminance of the edge area with weaker illuminance is close to the central area as much as possible, and the uniformity is considered.
In addition, as shown in fig. 19, due to the existence of the air between the packaging adhesives 3, the light B reaching the side wall of the packaging adhesive 3 1 Light ray C 1 Respectively pass through light rays B 2 Light ray C 2 To Z 1 The direction is deflected, and the light B is assumed to be in the absence of the grid wall 84 (the backlight module shown in FIG. 7) 2 Light ray C 2 There is still the possibility of impinging on the area where the surrounding unlit LED2 is located. In the backlight module shown in FIG. 19The presence of the grid wall 84 alters the light B 2 Light ray C 2 Respectively, and respectively pass through the light ray B 3 Light ray C 3 To the area of the extended plate 41 above the LEDs 2, thereby preventing this light from entering the surrounding area where the non-emitting LEDs 2 are located, and thus reducing the halo effect. Moreover, according to the description of the related contents of the embodiment shown in fig. 13, the air between the top of the encapsulant 3 and the diffusion layer 4 makes the light reach the top of the encapsulant 3 and may be fully emitted, thereby causing the loss of the light, and therefore, in the backlight module shown in fig. 16, by reflecting the light incident on the grid wall 84 to the area of the diffusion plate 41 above the LED2, the illuminance above the LED2 can be increased, and the light loss caused by the diffused light can be compensated.
In summary, compared to the backlight module shown in fig. 7, the backlight module shown in fig. 16 further uses the grid 8 to secondarily shield the light output from the sidewall and the top of the encapsulant 3, which may enter the surrounding area where the non-emitting LED2 is located. And, under the effect that has the secondary protection, through the clearance between diffusion layer 4 and the encapsulation glue 3, outwards diffuse the light at encapsulation glue 3 top to improve the illuminance of marginal area, thereby improve backlight unit's illuminance uniformity, and help reducing backlight unit's thickness. Due to the secondary protection, the light which is diffused outwards is not worried to be emitted into the area where the LED2 which does not emit light is located, so that the halo effect is caused. It should be understood that the existence of the grid 8 allows more light emitted from the encapsulant 3 to be transmitted to the grid wall 84 and then reflected back to the top of the LED2 by the grid wall 84, so that all light output by the LED2 is finally mixed by the grid 8 and then output, and therefore, the flat light source originally formed by the LED2 is expanded into a large-area uniform light source formed by the area surrounded by the grid wall 84 of the grid 83.
It should be noted that in fig. 16, the refractive index of the diffusion layer 4 may be larger than that of the encapsulant 3. In other embodiments, the index of refraction of the diffuser layer 4 is less than the index of refraction of the encapsulant 3 in order to provide better uniformity of illumination over the LED2, such that light rays refracted into the air from the top of the encapsulant 3 and entering the diffuser layer 4 from the air are farther awayFrom Z 1 Direction of light ray in X 1 The directions are more dispersed, and the edge of the packaging adhesive 3 has better illumination, so that the LED2 has better illumination uniformity.
Fig. 16 shows the structure of the secondary protection with the grid wall 84 of the grid 8. In other embodiments, the secondary protection may be performed by other members having a light reflection function. Illustratively, it may also be at X 1 An independent baffle (namely a clapboard unit) is arranged between two packaging adhesives 3 adjacent to each other in the direction for secondary protection. The individual baffles are discrete pieces compared to the unitary piece of grating 8. In this case, the shutter has two plate surfaces, one of which (i.e., the first plate surface) faces one of the adjacent two potting adhesives 3 (i.e., the first potting adhesive) and maintains a gap; the other plate (i.e., the second plate) faces the other sealing compound 3 (i.e., the second sealing compound) and maintains a gap, and the following embodiments are all described with reference to the grid wall 84 of the grid 8.
It should be understood that when the backlight module is along Z 1 When the thickness in the direction is relatively small, then, grid wall 84 is at Z 1 The height of the direction is lower. In some embodiments, please refer to FIG. 20, which is different from the backlight module shown in FIG. 19, the grid wall 84 of the backlight module is at Z 1 The height of the direction is lower. In this case, the light (e.g. light a) originally outputted from the side wall of the package adhesive 3 and the top of the package adhesive 3 onto the grid wall 84 2 Light ray B 2 ) Possibly transmitted through above the grid walls 84 and into the surrounding unlit LEDs 2, causing a halo effect. Based on this, the embodiment of the present application further provides a backlight module shown in fig. 21.
Referring to fig. 21, fig. 21 is a schematic structural diagram of a backlight module according to another embodiment of the present application. Unlike the backlight module shown in FIG. 16, the grid wall 84 is along X 1 Thickness in the direction Z 1 The direction gradually increases. In other words, the thickness of the grid wall 84 gradually decreases from the end away from the substrate 1 to the end close to the substrate 1, and the grid wall has a structure that is wide at the top and narrow at the bottom. Thus, for light ray A that may pass over grid wall 84 as shown in FIG. 20 2 Light ray B 2 It is shielded and reflected by the portion of the grid wall 84 extending by widening as shown in fig. 21, so that the light ray a 2 Light ray B 2 The ambient non-emitting LED2 cannot be irradiated, and the halo effect can be reduced.
It should be understood that in the backlight module shown in fig. 21, the grid wall 84 has light reflection output, so the grid wall 84 has brightness, but the top of the grid wall 84 (the end contacting with the diffusion layer 4) has no light output, so the top of the grid wall 84 is darker, so that a dark black ring (i.e. halo effect) appears at the periphery of the bright object displayed by the LED2, especially at X of the grid wall 84 1 The thickness in the direction is too thick (e.g., in FIG. 21, the grid wall 84 is placed above X 1 The thickness in the direction is widened), the performance becomes more remarkable. In addition, when most of the high angle light emitted from the LED2 is reflected by the grid wall 84 (e.g., the grid wall 84 is at Z) 1 High in height or wide above grid wall 84 as in fig. 21), there will be less light rays obliquely coming out from above grid wall 84, in which case the location where grid wall 84 is located appears darker overall when looking at the screen of the electronic device from an oblique perspective, thereby causing the human eye to look at the presence of interior grid wall 84.
In view of this, referring to fig. 22 (a), the corner of the end of the grid wall 84 away from the substrate 1 in fig. 21 is chamfered, so that a slope 85 is formed at the end of the grid wall 84 away from the substrate 1 with respect to the substrate 1. On the one hand, the area of the top of the grid wall 84, i.e. the area without light output, can be reduced, so that the area of the black ring can be reduced, and the halo effect can be reduced, and on the other hand, the light ray a originally blocked and reflected by the grid wall 84 shown in fig. 21 is reflected 2 Light ray B 2 Will be obliquely projected from the inclined plane 85 to above the top of the grid 83, compensates for the halo effect at the top of the grid 83 due to no light projection, and when the human eye looks at the screen of the electronic device from an oblique perspective, ray a 2 Light ray B 2 Can be injected into human eyes, so that the grid wall body 84 is positioned at a position which has brightness similar to that of the packaging adhesive 3 on the whole and can not be watched on the inner grid wallThe presence of body 84. Similarly, the backlight module shown in fig. 7 and 16 has the same problem. In other embodiments, referring to fig. 22 (b), the corner of the end of the grid wall 84 away from the substrate 1 in fig. 16 may also be chamfered, and a slope 85 is formed at the end of the grid wall 84 away from the substrate 1 and opposite to the substrate 1. In other embodiments, the corner of the end of the grid wall 84 away from the substrate 1 in fig. 7 may be chamfered, and a slope may be formed at the end of the grid wall 84 away from the substrate 1 relative to the substrate 1.
Referring to fig. 23a, fig. 23a is a schematic structural diagram of a backlight module according to another embodiment of the present application. Unlike the backlight module shown in fig. 16, in the backlight module, an arc-shaped groove 33 is formed at the top of the encapsulant 3. In this case, the top of the encapsulation glue 3 is equivalent to a concave lens. In addition, the side wall of the packaging adhesive 3 is along Z 1 The direction gradually approaches the optical axis. In other words, the side wall of the packaging adhesive 3 is along the Z 1 The direction inclines towards the optical axis to form a trapezoidal side wall. To facilitate the illustration of the structure of the packaging adhesive 3 shown in fig. 23a, fig. 23B shows a cross-sectional view of fig. 23a along the cutting line B-B. As shown in fig. 23b, the arc-shaped groove 33 on the top of the packaging adhesive 3 forms an oval ring-shaped area inside the edge line of the packaging adhesive 3. The top of the trapezoidal side wall (the side away from the substrate 1) forms an inner rectangular ring line M1 in the cross-sectional view, and the bottom of the trapezoidal side wall (the side closer to the substrate 1) forms an outer rectangular ring line M2 in the cross-sectional view.
The effect of the curved recesses 33, and the trapezoidal sidewalls on the light propagation path is specifically analyzed below in conjunction with fig. 24 and 25.
Referring to fig. 24, fig. 24 illustrates the influence of the structure on the top of the package adhesive 3 on the propagation direction of the refracted light. It should be noted that, for the sake of clarity, fig. 24 only illustrates the structure of the package adhesive 3 and the corresponding LED2 in fig. 23a, and only the light refracted from the top of the package adhesive 3 is retained. Wherein the dotted line a 1 Is a normal line of the interface between the top of the packaging adhesive 3 and the air, shown in fig. 16, and is a dotted line a 2 Light ray A is normal to the top of the packaging adhesive 3 shown in FIG. 23a and the interface with air 2 Is a light ray A 1 The exit direction of the refracted ray, ray A, when incident on the top of the encapsulant 3 shown in FIG. 16 3 Is a light ray A 1 The exit direction of the refracted rays when they strike the top of the encapsulant 3 shown in fig. 23 a. By contrast, it can be seen that by forming the arc-shaped groove 33 on the top of the packaging adhesive 3, the normal of the interface between the top of the packaging adhesive 3 and the air can be deflected counterclockwise. On the basis of the above, the light ray A 1 The corresponding incident angle and hence refraction angle become larger, and ray A becomes larger 1 After reaching the arcuate groove 33, it will be farther from Z at the arcuate groove 33 1 The direction deflects, thereby making light diffuse to the optical axis both sides, and then promoting the illuminance uniformity. It should be understood that the light incident on the top of the encapsulant 3 is substantially the light from the central region of the LED2, and therefore, the arc-shaped groove 33 has the function of diffusing the light output from the central region of the LED2 more outward, so as to weaken the high illuminance directly above the LED2 and improve the illuminance of the region other than the region directly above the LED2, thereby facilitating the improvement of the illuminance uniformity of the backlight module, and further reducing the thickness of the backlight module.
Referring to fig. 25, fig. 25 illustrates the influence of the sidewall structure of the package adhesive 3 on the propagation direction of the refracted light. It should be noted that, for the sake of clarity, fig. 25 only illustrates the structure of the package adhesive 3 and the corresponding LED2 in fig. 23a, and only the light refracted from the sidewall of the package adhesive 3 is retained. Wherein the dotted line b 1 Is a normal line of the interface of the side wall of the packaging adhesive 3 with air, shown in FIG. 16, and is a dotted line b 2 Light ray B is normal to the interface between the sidewall of the packaging adhesive 3 and air shown in FIG. 23a 2 Is a light ray B 1 The exit direction of the refracted ray, ray B, when it enters the side wall of the package adhesive 3 shown in FIG. 16 3 Is a light ray B 1 The light rays incident on the side wall of the package adhesive 3 shown in fig. 23a are refracted in the exit direction. Through comparison, the normal line of the interface between the side wall of the packaging adhesive 3 and the air can be deflected anticlockwise by inclining the side wall of the packaging adhesive 3 to the optical axis, so that the same light ray B reaching the side wall of the packaging adhesive 3 is enabled to be emitted 1 Finally can be towards Z 1 The direction is deflected. It will be appreciated that the light incident on the side walls of the encapsulant 3 is substantially transmitted from the edges of the LED2Therefore, the trapezoid side wall has the effect of enabling the large-angle light output by the edge of the LED2 to be converged, and the halo effect is further reduced. In addition, the light ray B 1 After deflection by the trapezoidal side wall, light ray B may finally pass 3 The light is directly irradiated into the gap between the grid wall 84 and the packaging adhesive 3, so that the brightness of the gap between the grid wall 84 and the packaging adhesive 3 is improved, and is not irradiated to the grid wall 84, which is more beneficial to enabling the area surrounded by the grid wall 84 to be equivalent to a large-area uniform light source.
It should be understood that, in other embodiments, on the basis of the backlight module shown in fig. 16, only the arc-shaped groove 33 is formed on the top of the packaging adhesive 3, or only the side wall of the packaging adhesive 3 is set as the trapezoid side wall. The louver 8 of the backlight unit shown in fig. 23a may be provided as shown in fig. 21 and 22. The embodiment of the present application is not particularly limited to this.
In some embodiments, in order to form the packaging adhesive 3 shown in fig. 23a, please refer to fig. 26, first, the steel net 7C (i.e. the third steel net) shown in fig. 26 (a) is designed. The steel net 7C has a first surface S1 and a second surface S2. As shown in fig. 26 (a), the steel net 7C includes boss regions 71C and non-opening regions 72C alternately arranged. Wherein the boss region 71C includes an arc-shaped boss structure 712C, and an opening region 711C surrounding the arc-shaped boss structure 712C; the open-cell area 711C has a cavity (i.e., a third cavity) and an opening (i.e., a third opening) for pouring the encapsulation glue into the cavity; two-by-two land regions 71C are separated by a non-apertured region 72C. As shown in fig. 26 (b), after the steel net 7C shown in fig. 26 (a) is obtained, it may be laid over the substrate 1 such that the land areas 71C are aligned with the areas where the LEDs 2 are located, the non-opening areas 72C are aligned with the gaps between two LEDs 2, and the first surface S1 of the laid steel net 7C is a surface away from the substrate 1. Then, the encapsulation glue solution is injected into the hole position where the LED2 is located from the hole opening area 711C by means of dispensing, spraying, brushing, and the like. Due to the existence of the arc-shaped boss structure 712C, the arc-shaped groove 33 can be formed at the top of the packaging adhesive 3, and due to the shape of the non-opening area 72C being an inverted trapezoid, the packaging adhesive 3 with the trapezoid-shaped side wall can be formed. Finally, curing is performed to form the packaging adhesive 3 shown in fig. 23a on the LED2, so as to realize the packaging of the LED 2.
The present application further provides a display device, which includes a display panel and the backlight module shown in any one of fig. 7 to 26. The technical effects of the display device can refer to the technical effects of the backlight module of the above embodiments, and are not described herein again.
As shown in fig. 27, an electronic device is further provided in the embodiments of the present application. The electronic device 00 includes a battery 01, a backlight module 02, and a display panel 03 stacked in sequence. The backlight module 02 shown in any one of fig. 7 to 26 is used for providing backlight to the display panel 03; the battery 01 is respectively connected with the backlight module 02 and the display panel 03 and used for supplying power to the backlight module 02 and the display panel 03.
The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily think of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims (9)

1. The packaging method of the backlight module is characterized by being used for packaging the backlight module, wherein the backlight module comprises a substrate and a plurality of Mini LEDs uniformly arranged on the substrate, and the Mini LEDs and packaging glue corresponding to the Mini LEDs are arranged on the surface of the substrate along the row direction and the column direction; the method comprises the following steps:
obtaining a third steel mesh; the third steel mesh is provided with a first surface and a second surface, the third steel mesh comprises a plurality of boss areas and a plurality of third non-perforated areas, each boss area comprises an arc-shaped boss structure and a perforated area surrounding the arc-shaped boss structure, the arc-shaped boss structures are projected from the first surface to the second surface, and each perforated area is provided with a third cavity and a third opening for pouring packaging glue solution into the third cavity; the boss areas and the third non-hole-opening areas are alternately arranged in the row direction and the column direction; two of the land regions adjacent in the row direction and two of the land regions adjacent in the column direction are separated by the third non-apertured region;
laying the third steel mesh above the substrate, so that the arc-shaped boss structure is opposite to the Mini LEDs, and the third non-hole-forming area is aligned to a gap between two adjacent Mini LEDs in the row direction and the column direction; in the laid third steel mesh, the first surface is the surface far away from the substrate;
pouring a packaging glue solution into the third cavity through the third opening to form a corresponding packaging glue on each MiniLED; each MiniLED is encapsulated by the independent encapsulation glue, and the encapsulation glue corresponding to two adjacent minileds is arranged at intervals in the row direction and the column direction; the top of the packaging adhesive is provided with an arc-shaped groove, and the side wall of the packaging adhesive is gradually close to the optical axis of the Mini LED corresponding to the packaging adhesive along a first direction; the first direction is perpendicular to the surface of the substrate and extends from the substrate to the direction where the Mini LED is located, and the side wall of the packaging adhesive refers to the area of the packaging adhesive except the top of the packaging adhesive and the bottom of the packaging adhesive; the top of the packaging adhesive refers to the side of the packaging adhesive far away from the substrate, and the bottom of the packaging adhesive refers to the side of the packaging adhesive close to the substrate.
2. The method of claim 1, wherein the Mini LEDs and the corresponding encapsulant are arranged along a row direction and a column direction on the substrate surface;
obtaining a fourth steel mesh; wherein the fourth steel mesh comprises a plurality of fourth perforated areas and a plurality of fourth non-perforated areas, the fourth perforated areas comprise fourth cavities and fourth openings for pouring grid glue into the fourth cavities, and the fourth non-perforated areas and the fourth perforated areas are alternately arranged in the row direction and the column direction; two of the fourth aperture regions adjacent in the row direction and two of the fourth aperture regions adjacent in the column direction are separated by the fourth non-aperture region;
laying the fourth steel mesh above the substrate, so that the fourth perforated area is aligned to a gap between two adjacent packaging adhesives, and the fourth non-perforated area covers the area where the packaging adhesives are located;
pouring a grid glue solution into the fourth cavity through the fourth opening of each fourth opening area to form a grid on the substrate; wherein the grid is provided with a plurality of grids, the single packaging glue is surrounded by the grid wall body of the single grid, and a gap is arranged between the grid wall body and the packaging glue;
and performing light reflection treatment on the wall surface of the grid wall body facing the packaging adhesive.
3. The method of claim 2, wherein the backlight module further comprises:
a diffusion layer and a light conversion film are sequentially laminated above the packaging adhesive along the first direction; and light rays output by the Mini LED sequentially pass through the corresponding packaging glue, the diffusion layer and the light conversion film to be output so as to provide backlight.
4. The method for encapsulating a backlight module according to claim 3, wherein the encapsulant and the diffusion layer are disposed at intervals;
the Mini LEDs and the packaging glue corresponding to the Mini LEDs are arranged on the surface of the substrate along the row direction and the column direction;
partition plate units are connected between two adjacent packaging glues in the row direction and between two adjacent packaging glues in the column direction, and a grid wall body of the grid is the partition plate unit;
the two adjacent packaging glues are respectively a first packaging glue and a second packaging glue; the partition plate unit is provided with a first plate surface facing the first packaging adhesive and a second plate surface facing the second packaging adhesive; the first plate surface and the second plate surface have a light reflection function;
the first packaging adhesive and the first board surface are arranged at intervals, and the second packaging adhesive and the second board surface are arranged at intervals.
5. The method of claim 4, wherein the spacer unit disposed between two adjacent encapsulation glues in the row direction has a thickness in the row direction; the spacer unit disposed between two of the encapsulation glues adjacent in the column direction has a thickness in the column direction;
the thickness of the diaphragm unit becomes gradually larger along the first direction.
6. The method of claim 4 or 5, wherein an end of the spacer unit adjacent to the diffusion layer has a slope;
the inclined surface is gradually closer to a center line of the diaphragm unit in the first direction.
7. The method of any of claims 3-5, wherein the diffuser layer comprises a diffuser plate, a diffuser film, and a brightness enhancement film stacked along the first direction.
8. A display device, comprising: a display panel arranged in a stack, and a backlight module manufactured by the method for packaging the backlight module according to any one of claims 1 to 7, wherein the backlight module is used for providing backlight for the display panel.
9. An electronic device, comprising a battery, a backlight module manufactured by the method for encapsulating a backlight module according to any one of claims 1 to 8, and a display panel, which are stacked in this order;
the backlight module is used for providing backlight for the display panel; the battery is respectively connected with the backlight module and the display panel and used for supplying power to the backlight module and the display panel.
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