CN116794885A

CN116794885A - Backlight module, manufacturing method thereof and liquid crystal display device

Info

Publication number: CN116794885A
Application number: CN202310804349.XA
Authority: CN
Inventors: 王玮; 王新星; 张方振; 牛菁; 孙双; 牛亚男; 任锦宇; 王锦谦
Original assignee: BOE Technology Group Co Ltd
Current assignee: BOE Technology Group Co Ltd
Priority date: 2023-06-30
Filing date: 2023-06-30
Publication date: 2023-09-22

Abstract

The embodiment of the disclosure provides a backlight module, a manufacturing method thereof and a liquid crystal display device. The backlight module comprises a substrate, a plurality of light emitting chips which are arranged on the first surface of the substrate in an array manner and emit light rays of a first color, a plurality of light conversion units which are connected with the substrate and correspond to the light emitting chips one by one, and a first reflecting layer which is positioned between the light conversion units. The light conversion unit is positioned on one side of the light emitting chip facing the substrate and comprises a scattering layer, a second reflecting layer and a light conversion layer which are sequentially arranged along the direction of the substrate pointing to the light emitting chip. The light conversion layer converts part of the light rays of the first color into light rays of the second color and light rays of the third color. The second reflecting layer reflects part of the light rays of the first color back to the light conversion layer and transmits the light rays of the second color, the third color and part of the light rays of the first color to form white light. The first reflecting layer reflects the white light emitted by the scattering layer to a second surface of the substrate opposite to the first surface. The embodiment of the disclosure can improve the color cast problem of the white light emitted by the backlight module.

Description

Backlight module, manufacturing method thereof and liquid crystal display device

Technical Field

The embodiment of the disclosure relates to the technical field of display, in particular to a backlight module, a manufacturing method thereof and a liquid crystal display device.

Background

The liquid crystal display device has the advantages of small volume, light weight, low radiation and the like, and is widely applied to various fields. The liquid crystal display device comprises a backlight module and a liquid crystal display panel, wherein the Mini LED backlight module has the advantages of ultrahigh resolution, high brightness, low power consumption, no splice gap, quick response and the like.

In the related art, the backlight module includes a substrate, a reflective layer, a plurality of light emitting chips, a phosphor layer, and a scattering layer. The reflecting layer is positioned on one side of the substrate, the plurality of light emitting chip arrays are arranged on one side of the reflecting layer away from the substrate, and the fluorescent powder layer and the scattering layer are sequentially positioned on one side of the plurality of light emitting chips away from the substrate. The light rays of the first color emitted by the light emitting chips are emitted after passing through the fluorescent powder layer and the scattering layer, wherein the fluorescent powder layer converts part of the light rays of the first color into light rays of other colors. The unconverted light of the first color and the light of the other colors are mixed to form white light.

Because the time for the light of the first color emitted by the light emitting chip to pass through the fluorescent powder layer is short, the converted light of other colors is less, and the white light emitted by the backlight module is easy to have color cast.

Disclosure of Invention

The disclosure provides a backlight module, a manufacturing method and a liquid crystal display device, which can improve the color cast problem of white light emitted by the backlight module.

In one aspect, a backlight module is provided, the backlight module includes a substrate, a plurality of light emitting chips, a plurality of light conversion units, and a first reflective layer; the light emitting chips are arranged on the first surface of the substrate and emit light rays of a first color; the light conversion units are connected with the substrate, the light conversion units are in one-to-one correspondence with the light emitting chips, and the light conversion units are positioned on one side, facing the substrate, of the corresponding light emitting chip; the light conversion unit comprises a scattering layer, a second reflecting layer and a light conversion layer which are sequentially arranged along the direction of the substrate pointing to the light emitting chip, wherein the light conversion layer is used for converting part of light rays of the first color into light rays of a second color and light rays of a third color, the second reflecting layer is used for reflecting part of the light rays of the first color back to the light conversion layer, and the part of the light rays of the first color, the light rays of the second color and the light rays of the third color are transmitted to form white light; the first reflecting layer is positioned between the plurality of adjacent light conversion units and is used for reflecting the white light emitted by the scattering layer to the second surface of the substrate, and the first surface is opposite to the second surface.

Optionally, the second reflective layer includes a plurality of first dielectric layers and a plurality of second dielectric layers alternately stacked, and a light refractive index of the first dielectric layers is different from a light refractive index of the second dielectric layers.

Optionally, the second reflective layer includes the first structural layer and a plurality of second structural layers stacked on the first structural layer, where the first structural layer includes two stacked first dielectric layers, and the second structural layer includes one stacked second dielectric layer and two stacked first dielectric layers; the thickness of the first dielectric layer is 50nm to 70nm, and the thickness of the second dielectric layer is 93nm to 113nm.

Optionally, the second reflective layer includes a plurality of stacked periodic structures, wherein the periodic structures include one of the first dielectric layers and one of the second dielectric layers; the thickness of the first dielectric layer is 35nm to 55nm, and the thickness of the second dielectric layer is 67nm to 87nm.

Optionally, the first dielectric layer is made of titanium dioxide, and the second dielectric layer is made of silicon dioxide.

Optionally, the second reflective layer has at least one opening therein.

Optionally, the ratio of the total area of orthographic projection of the at least one opening on the first surface to the area surrounded by the outline of orthographic projection of the second reflecting layer on the first surface is 30% -35%.

Optionally, the shape of the opening is circular, elliptical, square or elongated.

Optionally, the substrate further includes a plurality of protruding structures, the plurality of protruding structures are located on the first surface and between the adjacent plurality of light conversion units, and the first reflective layer is in contact with the protruding structures.

Optionally, the first reflective layer includes a first protective layer, a metal layer, and a second protective layer sequentially stacked.

Optionally, the substrate has a plurality of grooves therein, the plurality of groove arrays are arranged on the first surface, and the plurality of light conversion units are located in the plurality of grooves.

Optionally, the light conversion layer is a phosphor layer, or the light conversion layer is a quantum dot conversion layer.

Optionally, the backlight module further includes an encapsulation layer, the encapsulation layer is located between the plurality of light emitting chips and the first reflection layer, and the encapsulation layer includes a first sub-layer, a second sub-layer, and a third sub-layer that are stacked; the first sub-layer and the third sub-layer are made of inorganic materials, and the second sub-layer is made of organic materials.

In another aspect, a method for manufacturing a backlight module is provided, the method including: providing a substrate having opposing first and second surfaces; disposing a first reflective layer, a plurality of light conversion units, and a plurality of light emitting chips on the first surface; the light conversion units are arranged on the first surface, the light conversion units are connected with the substrate, the first reflecting layer is positioned between the adjacent light conversion units, the light emitting chip arrays are arranged on the first surface and correspond to the light emitting chips one by one, the light conversion units are positioned on one side of the corresponding light emitting chip, which faces the substrate, and the light conversion units comprise a scattering layer, a second reflecting layer and a light conversion layer which are sequentially arranged along the direction of the substrate pointing to the light emitting chip; the light conversion layer is used for converting part of the light rays of the first color into light rays of a second color and light rays of a third color, the second reflection layer is used for reflecting part of the light rays of the first color back to the light conversion layer and transmitting part of the light rays of the first color, the light rays of the second color and the light rays of the third color so as to form white light, and the first reflection layer is used for reflecting the white light emitted by the scattering layer to the second surface.

In a further aspect, a liquid crystal display device is provided, the liquid crystal display device comprising a liquid crystal display panel and a backlight module as claimed in any one of claims to provide a light source for the liquid crystal display panel.

The beneficial effects that this disclosure provided technical scheme brought include at least:

the second reflecting layer is arranged on one side, far away from the light emitting chip, of the light conversion layer, part of the light of the first color is reflected back to the light conversion layer, so that the conversion efficiency of the light of the second color and the light of the third color is improved, the light conversion layer converts more light of the second color and light of the third color, the proportion of the light of the second color and light of the third color in the emergent white light is improved, and the color cast problem of the white light emergent from the backlight module is improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required for the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present disclosure, and other drawings may be obtained according to these drawings without inventive effort for a person of ordinary skill in the art.

Fig. 1 is a schematic structural diagram of a liquid crystal display device according to an embodiment of the present disclosure;

fig. 2 is a schematic plan view of a backlight module according to an embodiment of the disclosure;

fig. 3 is a schematic view of a partial planar structure of a backlight module according to an embodiment of the disclosure;

fig. 4 is a schematic view of a partial cross-sectional structure of a backlight module according to an embodiment of the disclosure, and fig. 4 is a schematic view of a cross-sectional structure of fig. 3 along line AA;

FIG. 5 is a schematic cross-sectional view of a second reflective layer according to an embodiment of the present disclosure;

FIG. 6 is a spectral diagram corresponding to a second reflective layer according to an embodiment of the present disclosure;

FIG. 7 is a schematic cross-sectional view of another second reflective layer provided in an embodiment of the present disclosure;

FIG. 8 is a spectral diagram corresponding to another second reflective layer provided by an embodiment of the present disclosure;

fig. 9 is a flowchart of a method for manufacturing a backlight module according to an embodiment of the disclosure;

fig. 10 to 18 are schematic diagrams illustrating a manufacturing process of a backlight module according to an embodiment of the disclosure.

Legend description:

100. backlight module 200 and liquid crystal display panel

1. Substrate 10, bump structure 11, groove 101, first surface 102, second surface

2. Light emitting chip 3, light conversion unit 4, first reflective layer

5. Packaging layer 6, wiring 7, bonding pad 8 and solder mask

31. Scattering layer 32, second reflecting layer 33, light conversion layer

320. Openings (of the second reflecting layer)

321. First dielectric layer 322, second dielectric layer

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the present disclosure more apparent, the embodiments of the present application will be described in further detail below with reference to the accompanying drawings.

The terminology used in the description of the embodiments of the disclosure is for the purpose of describing the embodiments of the disclosure only and is not intended to be limiting of the disclosure. Unless defined otherwise, technical or scientific terms used in the embodiments of the present disclosure should be given the ordinary meaning as understood by one of ordinary skill in the art to which the present disclosure belongs. The terms "first," "second," "third," and the like in the description and in the claims, do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. Likewise, the terms "a" or "an" and the like do not denote a limitation of quantity, but rather denote the presence of at least one. The word "comprising" or "comprises", and the like, is intended to mean that elements or items that are present in front of "comprising" or "comprising" are included in the word "comprising" or "comprising", and equivalents thereof, without excluding other elements or items.

Fig. 1 is a schematic structural diagram of a liquid crystal display device according to an embodiment of the disclosure. As shown in fig. 1, the liquid crystal display device includes a backlight module 100 and a liquid crystal display panel 200 which are stacked. The liquid crystal display panel 200 is located on the light emitting side of the backlight module 100, and the shape and size of the liquid crystal display panel 200 are generally matched with those of the backlight module 100. For example, when the liquid crystal display device 200 is applied to a television or a mobile terminal, etc., the liquid crystal display panel 200 and the backlight module 100 may be arranged in a rectangular shape. The liquid crystal display panel 200 is a transmissive display panel, and is capable of modulating the transmittance of light, but does not emit light itself, and the backlight module 100 is required to provide a light source for the liquid crystal display panel 200 to realize brightness display. The liquid crystal display panel 200 has a plurality of pixel units arranged in an array, and each pixel unit can independently control the transmittance and color of the light incident on the pixel unit by the backlight module 100, so that the light emitted by all the pixel units forms a displayed image.

The backlight module in the embodiment of the disclosure adopts a direct type backlight module for uniformly emitting light in the light emitting surface, and providing light with sufficient brightness and uniform distribution for the display panel so that the display panel can normally display images.

Fig. 2 is a schematic plan view of a backlight module according to an embodiment of the disclosure. As shown in fig. 2, the backlight module 100 includes a substrate 1 and a plurality of light emitting chips 2. A plurality of light emitting chips 2 are arranged in an array at the first surface 101 of the substrate 1.

Fig. 3 is a schematic view of a partial planar structure of a backlight module according to an embodiment of the disclosure, fig. 4 is a schematic view of a partial cross-sectional structure of a backlight module according to an embodiment of the disclosure, and fig. 4 is a schematic view of a cross-sectional structure of fig. 3 along line AA. As shown in fig. 3 and fig. 4, the substrate 1 has a first surface 101 and a second surface 102 opposite to each other, wherein the first surface 101 is far away from the light emitting surface of the backlight module 100, and the second surface 102 is near to the light emitting surface of the backlight module 100. The backlight module 100 further includes a plurality of light conversion units 3 and a first reflective layer 4.

Illustratively, the driving modes of the backlight module 100 in the embodiment of the present disclosure include the following two types: PM (Passive Matrix, passive Matrix drive) and AM (Active Matrix, active Matrix vibration). Wherein the passive driving finger is connected with an IC (Integrated Circuit ) chip for driving. At this time, the backlight module 100 further includes a driving IC (Integrated Circuit ) connected to the substrate 1. The substrate 1 of the backlight module 100 under active driving further includes a TFT (Thin Film Transistor ) through which driving is performed.

As shown in fig. 4, a plurality of light conversion units 3 are connected to the substrate 1, the plurality of light conversion units 3 are in one-to-one correspondence with the plurality of light emitting chips 2, and the light conversion units 3 are located on the side of the corresponding one of the light emitting chips 2 facing the substrate 1; the light conversion unit 3 includes a scattering layer 31, a second reflection layer 32, and a light conversion layer 33, which are sequentially arranged in a direction in which the substrate 1 is directed toward the light emitting chip 2. The first reflection layer 4 is located between the adjacent plurality of light conversion units 3.

The light emitting chip 2 emits light of a first color, and the light conversion layer 33 is configured to convert part of the light of the first color into light of a second color and light of a third color. After the light of the first color, the light of the second color and the light of the third color reach the second reflecting layer 32, the second reflecting layer 32 reflects part of the light of the first color back to the light converting layer 33 to improve the conversion efficiency of the light of the second color and the light of the third color, and simultaneously, the light of the second color, the light of the third color and part of the light of the first color pass through the second reflecting layer 32. The diffusion layer 31 is used for diffusing the light emitted from the second reflection layer 32. The first reflective layer 4 is for reflecting light exiting from the scattering layer 31 to the second surface 102 of the substrate 1.

White light can be formed when the light of the first color, the light of the second color and the light of the third color are mixed in a certain proportion. If the second reflective layer 32 is not present, the light conversion layer 33 does not convert the light of the first color sufficiently, which results in an excessively high proportion of the light of the first color in the light emitted from the backlight module, and an excessively low proportion of the light of the second color and the light of the third color, which results in color cast of the white light emitted from the backlight module. The second reflective layer 32 can reflect the light of the first color back to the light conversion layer, so that the light conversion layer can convert more light of the second color and the third color, and the color shift problem of the white light emitted by the backlight module is improved.

Optionally, the first color is blue, and the second color and the third color are red and green, respectively. Alternatively, red, green, and blue light may be mixed in a ratio of 1:4.5907:0.0601 to form white light.

Illustratively, as shown in fig. 4, the substrate 1 has a plurality of grooves 11 therein, the plurality of grooves 11 being arranged in an array at the first surface 101 of the substrate, the light converting unit 3 being located in the plurality of grooves. The light conversion units 3 are located in the grooves, so that the surface, close to the light emitting chip 2, of the light conversion units 3 is flush with the surface, close to the light emitting chip 2, of the first reflecting layer 4, and therefore packaging is facilitated, a flat packaging surface is formed, and the light emitting chip 2 and the flat packaging surface are assembled conveniently.

Alternatively, the substrate 1 does not have a plurality of grooves, the first surface 101 is flat, and the plurality of light conversion units 3 are located on the first surface 101 of the substrate 1.

Alternatively, the substrate 1 may be any transparent substrate, such as a glass substrate, a quartz substrate, a plastic substrate, or the like.

Illustratively, the light conversion layer 33 is a phosphor layer, or the light conversion layer 33 is a quantum dot conversion layer. Both materials can convert light of a first color into light of a second color and light of a third color.

In the presently disclosed embodiment, the second reflective layer 32 has at least one aperture therein. The arrangement of the openings can prevent the light of the first color emitted by the backlight module 100 from being low in proportion, and reduce the color shift of the emitted white light. Illustratively, as shown in FIG. 4, the second reflective layer 32 has two openings 320 therein.

Illustratively, the ratio of the total area of the orthographic projection of the at least one opening 320 on the first surface 101 of the substrate 1 in the second reflective layer 32 to the area enclosed by the outer contour of the orthographic projection of the second reflective layer 32 on the first surface 101 of the substrate is 30% -35%. The aperture area ratio of the reflecting layer is set to be 30-35%, such as 31.5% -33.5%, for example, 1/3, so that the emergent red-green-blue light ratio is as close to an ideal state as possible, such as 1:4.5907:0.0601, and the color shift of the formed white light is reduced as much as possible.

Alternatively, the aperture may be circular, oval, square or elongated in shape. As shown in fig. 4, the openings are elongated in shape. These shaped apertures each allow light of the first color to pass through the second reflective layer 32. Because the second reflective layer 32 is thicker and comprises two dielectric layer materials, there is an etching selectivity ratio, so that openings with larger areas are easily etched in the second reflective layer 32, and openings with smaller areas are not easily etched in the second reflective layer 32.

FIG. 5 is a schematic cross-sectional view of a second reflective layer according to an embodiment of the present disclosureA drawing. As shown in fig. 5, the second reflection layer 32 includes a plurality of first dielectric layers 321 and a plurality of second dielectric layers 322 alternately stacked in layers, and the optical refractive index of the first dielectric layers 321 and the optical refractive index of the second dielectric layers 322 are different. The optical thickness of each first or second dielectric layer material is designed to be 1/4 of the central reflection wavelength, i.e. d=λ ₀ 4n, wherein d is the thickness of the first dielectric layer 321 or the second dielectric layer 322, lambda ₀ N is the refractive index of the first dielectric layer 321 or the second dielectric layer 322, which is the wavelength of the light emitted from the light emitting chip 2. The structure in which the first dielectric layers 321 and the second dielectric layers 322 having different refractive indexes are alternately stacked has a reflection effect.

Illustratively, the first dielectric layer 321 is made of titanium dioxide and the second dielectric layer 322 is made of silicon dioxide. Wherein titanium dioxide is a high refractive index material, the refractive index n is approximately equal to 2.5, and H is used for referring to a first dielectric layer; the silicon dioxide material is a low refractive index material, the refractive index n is approximately equal to 1.45, and L is used for referring to a second dielectric layer. And the first dielectric layer 321 made of titanium dioxide has higher hardness, so that the comprehensive performance of the reflecting layer can be improved. The second dielectric layer 322 made of silicon dioxide is not easy to decompose and absorb, and has good scattering property.

Alternatively, the second reflective layer 32 includes a first structural layer including two first dielectric layers 321 stacked and a plurality of second structural layers stacked on the first structural layer including one second dielectric layer 322 and two first dielectric layers 321 stacked. The thickness of the first dielectric layer 321 is 50nm to 70nm, and the thickness of the second dielectric layer 322 is 93nm to 113nm. Fig. 6 is a spectrum diagram corresponding to a second reflective layer according to an embodiment of the disclosure. As shown in fig. 6, the following four types of reflectivities of the second reflective layer 32 were calculated by simulation using commercial software TFCalc: HHLHH, HHLHHLHH, HHLHHLHHLHH, HHLHHLHHLHHLHH the four second reflective layers 32 correspond to the case where the number of the second structural layers is one, two, three, and four, respectively. Where HH is the half wavelength spacer layer and L is the coupling layer. The results of the simulation calculations are: the reflectivity of the third and fourth second reflecting layers to blue light (at 450 nm) is more than 90%, the reflectivity meets the requirement, and the reflectivity of the fourth second reflecting layer to blue light is higher.

Illustratively, as shown in fig. 5, the second reflective layer 32 includes a first structural layer and three second structural layers, i.e., the first dielectric layer 321 and the second dielectric layer 322 in the second reflective layer 32 are stacked in a manner of HHLHHLHHLHH. As can be seen from FIG. 6, the ideal reflectance of blue light by the second reflective layer 32 can be 93.7%, and the cost is lower than that of a second reflective layer composed of one first structural layer and four second structural layers.

For half-wavelength spacer layers, i.e., two continuous H layers, one H layer was first fabricated and then the second H layer was fabricated. Ideally, when the process conditions are identical, no interface is observed between the two H layers. When the process conditions are different, an interface between the two H layers can be observed by using a TEM (Transmission Electron Microscope ) or the like.

Fig. 7 is a schematic diagram of an interface structure of another second reflective layer according to an embodiment of the present disclosure. As shown in fig. 7, the second reflective layer 32 includes a plurality of periodic structures stacked, wherein the periodic structures include one first dielectric layer 321 and one second dielectric layer 322 stacked. The thickness of the first dielectric layer 321 is 35nm to 55nm, and the thickness of the second dielectric layer 322 is 67nm to 87nm.

FIG. 8 is a spectral diagram corresponding to another second reflective layer provided by an embodiment of the present disclosure. As shown in fig. 8, the reflectivities of the second reflective layers 32, which contain 1 to 7 periodic structures, were calculated by simulation using commercial software TFCalc, respectively. For example, the second reflective layer 32 including 5 periodic structures is stacked in a manner of HLHLHLHLHL. As can be obtained from the results, when the number of periodic structures is 4, 5, 6, and 7, respectively, the reflectance of the second reflective layer 32 to blue light sequentially increases and is greater than 90%, and the reflectance satisfies the requirement.

Illustratively, as shown in fig. 7, the second reflective layer 32 includes four stacked periodic structures, that is, the first dielectric layer 321 and the second dielectric layer 322 in the second reflective layer 32 are stacked in the following manner: HLHLHLHL. As can be seen from FIG. 8, the ideal reflectivity of the second reflective layer for blue light can be 93.5%, and the cost is lower than that of other second reflective layers.

It should be noted that, in practical applications, the second reflective layer 32 may be adjusted and weighted according to actual product requirements, for example, a second reflective layer with higher reflectivity and higher cost may be selected.

In the presently disclosed embodiment, referring again to fig. 3 and 4, the substrate 1 further comprises a plurality of raised structures 10, the raised structures 10 being located on the first surface 101 of the substrate and between adjacent light converting units 3, the first reflective layer 4 being in contact with the raised structures 10. Since the first reflective layer 4 contacts with the plurality of convex structures 10, the surface of the first reflective layer 4 is uneven and also has a plurality of protrusions, so that the plurality of protrusions can reflect the light emitted from the scattering layer 31 at multiple angles on the first reflective layer 4, thereby improving the uniformity of the light emitted from the backlight module 100, compared with the first reflective layer having a flat surface. It should be noted that, for clarity of illustration, the plurality of raised structures 10 of the first reflective layer 4 in fig. 4 are indicated by dashed circles.

Alternatively, the raised structures 10 are frustoconical, hemispheric or pyramidal. The plurality of convex structures of these shapes can reflect the light rays exiting from the scattering layer 31 at multiple angles.

In other possible embodiments, the first surface 101 of the substrate is planar, without the raised structures 10, and the first reflective layer 4 is in contact with the first surface 101 of the substrate, so the surface of the first reflective layer 4 is also planar. The first reflective layer 4 with a flat surface can reflect the light emitted from the scattering layer 31 out of the backlight module 100.

Illustratively, the first reflective layer 4 includes a first protective layer, a metal layer, and a second protective layer, which are sequentially stacked. Wherein, the metal layer can reflect light, and first protective layer and second protective layer protect the metal layer from oxidation etc..

Optionally, the metal layer is made of silver, and the first protective layer and the second protective layer are made of transparent materials such as indium tin oxide, so that the silver is protected from oxidation, and light can pass through ITO to reach the silver layer and be reflected.

Illustratively, as shown in fig. 4, in combination with the manner of integrating the first reflection layer 4 on the substrate 1 and the manner of arranging the light conversion unit 3 by making the groove 11 on the substrate 1, the thinning of the backlight module 100 may be further achieved.

Illustratively, as shown in fig. 4, the backlight module 100 further includes an encapsulation layer 5, where the encapsulation layer 5 is located between the plurality of light emitting chips 2 and the first reflective layer 4, and the front projection of the plurality of light emitting chips 2 on the first surface 101 of the substrate 1 is at least partially misaligned with the front projection of the first reflective layer 4 on the first surface 101 of the substrate 1. The encapsulation layer 5 covers the plurality of light conversion units 3 and the first surface 101 of the first reflective layer 4.

Optionally, the encapsulation layer 5 comprises a laminated first, second and third sub-layer; the first sub-layer and the third sub-layer are made of inorganic materials, and the second sub-layer is made of organic materials. The inorganic material can prevent water and oxygen from entering, and the organic material plays a role in planarization. Alternatively, the inorganic material includes SiO2 (silicon oxide), si ₃ N ₄ (silicon nitride), siON (silicon oxynitride). The organic material includes a resin and the like.

Alternatively, the scattering layer 31 is made of a resin and a plurality of scattering particles uniformly dispersed in the resin material. The scattering particles include, but are not limited to, metal particles, and the like.

As illustrated in fig. 3 and 4, the backlight module 100 further includes a trace 6 and a pad 7, and the trace 6 and the pad 7 are located on a side of the substrate 1 near the light emitting chip 2. The light emitting chip 2, the bonding pad 7 and the trace 6 are sequentially connected. The light emitting chip 2 can be supplied with power by the wiring 6. The bonding pads 7 can fix the light emitting chip 2 and the traces 6. Alternatively, as shown in fig. 3, two sets of traces 6 and pads 7 are located on both sides of the light conversion unit 3, respectively. Alternatively, the trace 6 is made of copper.

Illustratively, as shown in fig. 4, the backlight module 100 further includes a solder mask layer 8 for protecting the light emitting chip 2. Optionally, the solder mask layer 8 is white oil ink, and the white oil ink can play a role in solder mask and a certain light reflection, and has the advantages of stable performance, good light reflection, long-term difficult yellowing, high temperature resistance and the like.

Fig. 9 is a flowchart of a method for manufacturing a backlight module according to an embodiment of the disclosure. As shown in fig. 9, the method includes:

in step S1, a substrate is provided, the substrate having a first surface and a second surface opposite to each other.

In step S2, a first reflective layer, a plurality of light conversion units, and a plurality of light emitting chips are disposed on the first surface.

The light conversion units are arranged on the first surface, the light conversion units are connected with the substrate, the first reflecting layer is positioned between the adjacent light conversion units, the light emitting chip arrays are arranged on the first surface and correspond to the light emitting chips one by one, the light conversion units are positioned on one side of the corresponding light emitting chip, which faces the substrate, and the light conversion units comprise a scattering layer, a second reflecting layer and a light conversion layer which are sequentially arranged along the direction of the substrate pointing to the light emitting chip;

the light conversion layer is used for converting part of the light rays of the first color into light rays of a second color and light rays of a third color, the second reflection layer is used for reflecting part of the light rays of the first color back to the light conversion layer and transmitting part of the light rays of the first color, the light rays of the second color and the light rays of the third color so as to form white light, and the first reflection layer is used for reflecting the white light emitted by the scattering layer to the second surface of the substrate, wherein the first surface is opposite to the second surface.

Fig. 10 to 18 are schematic diagrams illustrating a manufacturing process of a backlight module according to an embodiment of the disclosure, and an exemplary method for manufacturing a backlight module, which may manufacture the backlight module shown in fig. 4, is described in detail below.

First, as shown in fig. 10, a photoresist layer is coated on a substrate 1, and a photoresist pattern is formed through a photolithography process; then, the surface of the substrate 1 is etched under the mask of the photoresist pattern. Alternatively, the substrate is a glass substrate and the etching method is ICP (Inductively Coupled Plasma ) etching.

In the second step, as shown in fig. 11, etching is continued on the surface of the substrate 1, and at this time, a part of the upper surface of the photoresist is removed, and a plurality of pits are formed on the surface of the substrate 1. Optionally, the etching method is ICP, and the pit is in the shape of an inverted truncated cone.

And thirdly, as shown in fig. 12, continuing to etch the surface of the substrate 1 until the photoresist is completely etched, and forming a plurality of raised structures on the surface of the substrate. Then, a photoresist pattern is formed again at a position corresponding to the light emitting chip. Optionally, the etching method is ICP.

In the fourth step, as shown in fig. 13, an initial first reflective layer 4' is formed on the surface of the substrate 1. Optionally, the initial first reflective layer is formed by sputtering.

Fifth, as shown in fig. 14, the photoresist is removed, so that a part of the initial first reflective layer on the photoresist is removed, and the first reflective layer 4 is obtained. Alternatively, lift-off (lift-off) processes are used to remove the photoresist.

Sixth, as shown in fig. 15, a plurality of grooves 111 are formed by recessing the portion of the surface of the substrate 1 where the first reflective layer 4 is not formed. Optionally, the first reflective layer 4 is used as a hard mask, and the substrate is etched and grooved with an etching solution. Optionally, the etching solution is hydrofluoric acid.

Seventh, as shown in fig. 16, a scattering layer 31, a second reflection layer 32, and a light conversion layer 33 are sequentially formed in the groove 111, resulting in the light conversion unit 3. And then forming an encapsulation layer 5 on the surfaces of the light conversion unit 3 and the first reflection layer 4. Alternatively, the scattering layer 31 is formed by printing. Optionally, an initial second reflective layer is formed on the scattering layer 31 and patterned using a series of photoresist coating, exposure, etching, stripping, etc., to provide a second reflective layer 32. Alternatively, the light conversion layer is formed by printing green and red phosphor layers for achieving white light conversion. Optionally, the encapsulation layer 5 is formed by deposition.

Eighth step, as shown in fig. 17, the trace 6 and the pad 7 are formed on the encapsulation layer 5. Optionally, the wire 6 and the pad 7 are fabricated using an electroplating process.

A ninth step, as shown in fig. 18, a plurality of light emitting chips (LEDs) 2 are fixed to other structures and packaged with a solder resist layer 8. Optionally, a plurality of light emitting chips (LEDs) 2 are fixed with other structures by wires 6 by using processes such as die bonding and reflow soldering.

Tenth, the substrate 1 is thinned, and the backlight module shown in fig. 4 is manufactured.

The embodiment of the disclosure further provides a liquid crystal display device, which includes a liquid crystal display panel 200 and any of the backlight modules 100 described above, wherein the backlight module 100 is configured to provide a light source for the liquid crystal display panel.

Optionally, the liquid crystal display device further comprises a power supply circuit, wherein the power supply circuit is used for supplying power to the liquid crystal display panel and the backlight module.

The display device provided by the embodiment of the disclosure may be any product or component with a display function, such as a mobile phone, a tablet computer, a television, a display, a notebook computer, a digital photo frame, a navigator, and the like.

The liquid crystal display device has the same effect as the backlight module and is not described herein.

The foregoing is merely an alternative embodiment of the present disclosure, and is not intended to limit the present disclosure, any modification, equivalent replacement, improvement, etc. that comes within the spirit and principles of the present disclosure are included in the scope of the present disclosure.

Claims

1. The backlight module (100) is characterized by comprising a substrate (1), a plurality of light emitting chips (2), a plurality of light conversion units (3) and a first reflecting layer (4);

the plurality of light emitting chips (2) are arranged on the first surface (101) of the substrate (1) in an array, and the plurality of light emitting chips (2) emit light rays of a first color;

the light conversion units (3) are connected with the substrate (1), the light conversion units (3) are in one-to-one correspondence with the light emitting chips (2), and the light conversion units (3) are positioned on one side, facing the substrate (1), of the corresponding light emitting chip (2);

the light conversion unit (3) comprises a scattering layer (31), a second reflecting layer (32) and a light conversion layer (33) which are sequentially arranged along the direction of the substrate (1) pointing to the light emitting chip (2), wherein the light conversion layer (33) is used for converting part of the light rays of the first color into the light rays of the second color and the light rays of the third color, the second reflecting layer (32) is used for reflecting part of the light rays of the first color back to the light conversion layer (33), and transmitting part of the light rays of the first color, the light rays of the second color and the light rays of the third color so as to form white light;

the first reflecting layer (4) is located between the adjacent light conversion units (3) and is used for reflecting white light emitted by the scattering layer (31) to a second surface (102) of the substrate (1), and the first surface (101) is opposite to the second surface (102).

2. A backlight module according to claim 1, wherein the second reflective layer (32) comprises a plurality of first dielectric layers (321) and a plurality of second dielectric layers (322) stacked alternately, the first dielectric layers (321) having a light refractive index different from the light refractive index of the second dielectric layers (322).

3. A backlight module according to claim 2, wherein the second reflective layer (32) comprises a first structural layer and a plurality of second structural layers stacked on the first structural layer, wherein the first structural layer comprises two stacked first dielectric layers (321), and the second structural layer comprises one stacked second dielectric layer (322) and two stacked first dielectric layers (321);

the thickness of the first dielectric layer (321) is 50nm to 70nm, and the thickness of the second dielectric layer (322) is 93nm to 113nm.

4. A backlight module according to claim 2, wherein the second reflective layer (32) comprises a plurality of stacked periodic structures, wherein the periodic structures comprise one of the first dielectric layers (321) and one of the second dielectric layers (322) stacked;

the thickness of the first dielectric layer (321) is 35nm to 55nm, and the thickness of the second dielectric layer (322) is 67nm to 87nm.

5. A backlight module according to any one of claims 2-4, wherein the first dielectric layer (321) is made of titanium dioxide and the second dielectric layer (322) is made of silicon dioxide.

6. A backlight module according to any one of claims 1-4, wherein the second reflective layer (32) has at least one aperture (320) therein.

7. A backlight module according to claim 6, wherein the ratio of the total area of the orthographic projection of the at least one opening (320) on the first surface (101) to the area enclosed by the outer contour of the orthographic projection of the second reflective layer (32) on the first surface (101) is 30% -35%.

8. A backlight module according to claim 7, wherein the aperture (320) has a shape of a circle, an ellipse, a square or a strip.

9. A backlight module according to any one of claims 1 to 4 and 7 to 8, wherein the substrate (1) further comprises a plurality of raised structures (10), the plurality of raised structures (10) being located at the first surface (101) and between adjacent ones of the plurality of light converting units (3), the first reflective layer (4) being in contact with the raised structures (10).

10. A backlight module according to any one of claims 1 to 4 and 7 to 8, wherein the first reflective layer (4) comprises a first protective layer, a metal layer and a second protective layer laminated in this order.

11. A backlight module according to any one of claims 1 to 4 and 7 to 8, wherein the substrate (1) has a plurality of grooves (11), the plurality of grooves (11) being arranged in an array at the first surface (101), the plurality of light converting units (3) being located within the plurality of grooves (11).

12. A backlight module according to any one of claims 1 to 4 and 7 to 8, wherein the light conversion layer (33) is a phosphor layer or the light conversion layer (33) is a quantum dot conversion layer.

13. A backlight module according to any one of claims 1 to 4 and 7 to 8, wherein the backlight module (100) further comprises an encapsulation layer (5), the encapsulation layer (5) being located between the plurality of light emitting chips (2) and the first reflective layer (4), the encapsulation layer (5) comprising a laminated first, second and third sub-layer;

the first sub-layer and the third sub-layer are made of inorganic materials, and the second sub-layer is made of organic materials.

14. The manufacturing method of the backlight module is characterized by comprising the following steps:

providing a substrate having opposing first and second surfaces;

disposing a first reflective layer, a plurality of light conversion units, and a plurality of light emitting chips on the first surface;

the light conversion layer is used for converting part of the light rays of the first color into light rays of a second color and light rays of a third color, the second reflection layer is used for reflecting part of the light rays of the first color back to the light conversion layer and transmitting part of the light rays of the first color, the light rays of the second color and the light rays of the third color so as to form white light, and the first reflection layer is used for reflecting the white light emitted by the scattering layer to the second surface.

15. A liquid crystal display device, characterized in that the liquid crystal display device comprises a liquid crystal display panel and a backlight module according to any of claims 1 to 13, the backlight module (100) providing a light source for the liquid crystal display panel (200).