WO2023216677A1 - Backlight module and preparation method therefor, and liquid crystal display panel - Google Patents

Abstract

A backlight module and a preparation method therefor, and a liquid crystal display panel. According to the backlight module (10), a quantum dot element containing a fluorescence-quenched quantum dot material is matched with an LED light source (11) for use, and the characteristic that the fluorescence-quenched quantum dot absorbs light and does not emit light and the characteristic that the absorption band is adjustable are utilized to absorb light in a crosstalk waveband, such that the color gamut is improved, and the display effect is better. In addition, compared with a light-emitting quantum dot material, the fluorescence-quenched quantum dot material has the advantages of high stability, low reliability process requirements and low cost.

Description

Backlight module and preparation method thereof, liquid crystal display panel

This application requires the priority of the Chinese patent application submitted to the State Intellectual Property Office of China on May 13, 2022, with the application number 202210522512.9 and the invention name "Backlight Module and Preparation Method, Liquid Crystal Display Panel", and its entire content has been approved This reference is incorporated into this application.

Technical field

The present disclosure relates to the field of display technology, and in particular to a backlight module, a preparation method thereof, and a liquid crystal display panel.

Background technique

Liquid crystal display devices (LCDs, Liquid Crystal Display) have many advantages such as thin body, power saving, and no radiation, and have been widely used. Most of the liquid crystal display devices currently on the market are backlight-type liquid crystal display devices, which include a liquid crystal panel and a backlight module. The working principle of the LCD panel is to place liquid crystal molecules between two parallel glass substrates. There are many vertical and horizontal small wires between the two glass substrates. The liquid crystal molecules are controlled to change direction by whether they are energized or not, and the light from the backlight module is refracted. Come out to produce a picture. Since the LCD panel itself does not emit light, it requires the light source provided by the backlight module to display images normally. Therefore, the backlight module has become one of the key components of the LCD device.

Backlight modules are divided into two types: side-type backlight modules and direct-type backlight modules according to the different incident positions of the light sources. The edge-type backlight module installs an LED (LightEmitting Diode) light bar on the edge of the back panel behind the LCD panel. The light emitted by the LED light bar enters the light from the side of the light guide plate (LGP, Light Guide Plate). The surface enters the light guide plate, and after reflection and diffusion, it is emitted from the light exit surface of the light guide plate, and then passes through the optical film group to form a surface light source and provides it to the LCD panel; the direct backlight module sets the LED light source behind the LCD panel to directly form a surface light source. The light source is provided to the LCD panel. In a direct-lit backlight module, a diffusion plate is required to diffuse light and support the optical film; the light emitted by the light source is effectively diffused through the diffusion plate, which can achieve better optical effects.

technical problem

There are many problems in the development process of backlight modules. For example, the color gamut of traditional LED light sources needs to be improved, which affects the display effect.

Technical solutions

Embodiments of the present disclosure provide a backlight module, a preparation method thereof, and a liquid crystal display panel, aiming to improve the problem of poor display effects of existing backlight modules.

In a first aspect, an embodiment of the present disclosure provides a backlight module, including: a quantum dot element and an LED light source disposed on one side of the quantum dot element; wherein the material of the quantum dot element includes quantum dots quenched by fluorescence. Point materials.

Optionally, the characteristic absorption peak of the fluorescence-quenched quantum dot material is 480 to 520 nm.

Optionally, the quantum dot element is a quantum dot film, a quantum dot diffusion plate or a quantum dot coating.

Optionally, the backlight module is a direct backlight module, and the LED light sources are distributed in an array; wherein, the quantum dot elements are quantum dot diffusion plates, and the light output between the quantum dot diffusion plates and the LED light sources is Face to face.

Optionally, the backlight module is a direct-type backlight module, and the LED light sources are distributed in an array. The backlight module also includes a diffusion plate, and the diffusion plate is opposite to the light exit surface of the LED light source; wherein, The quantum dot element is a quantum dot film or a quantum dot coating, and the quantum dot film or quantum dot coating is provided on a side of the diffusion plate away from the LED light source.

Optionally, the backlight module is an edge-type backlight module, and the backlight module further includes a light guide plate provided on one side of the quantum dot element and an LED light bar provided on the end surface of the light guide plate, so The LED light source is provided on the LED light bar; wherein the quantum dot element is a quantum dot film or a quantum dot coating.

Optionally, the quantum dot film includes: a quantum dot glue layer and a PET layer coated on the upper and lower surfaces of the quantum dot glue layer; the material of the quantum dot glue layer includes: the fluorescence quenched quantum dot material and colloid.

Optionally, the thickness of the quantum dot glue layer is 40~100 μm, the thickness of the PET layer is 60~120 μm, and the total thickness of the quantum dot film is 180~320 μm.

Optionally, the material of the quantum dot diffusion plate includes: the fluorescence-quenched quantum dot material and light-transmitting plastic; the light-transmitting plastic includes at least one of PS, PC or PMMA.

Optionally, the quantum dot diffusion plate is a single layer, and the material of the quantum dot diffusion plate is uniformly mixed quantum dot material that is quenched by fluorescence and light-transmitting plastic.

Optionally, the quantum dot diffusion plate is multi-layered, and the structure of the quantum dot diffusion plate is an upper and lower light-transmitting plastic layer and a film layer made of a quantum dot material solution in the middle.

Optionally, the quantum dot coating includes: the fluorescence quenched quantum dot material and colloid.

Optionally, the LED light source includes a blue light chip, red phosphor and green phosphor; the red phosphor is selected from YAGA and/or New Red Powder, and the green phosphor is selected from β-SIAION and/or nitride fluorescence pink.

Optionally, the emission wavelength of the green phosphor is 490~600nm.

Optionally, the fluorescence-quenched quantum dot material is treated with a quencher, and the quencher is selected from at least one of Fe ³⁺ , Co ²⁺ , Ag ⁺ , o-nitrophenol, and chlorogenic acid. kind.

Optionally, the quantum dots are selected from at least one of CdSe, CdTe, InP, silicon quantum dots or graphene quantum dots.

In a second aspect, embodiments of the present disclosure also provide a method for preparing a backlight module, including the steps of: providing a quantum dot material quenched by fluorescence; making the quantum dot material quenched by fluorescence into a quantum dot element; and An LED light source is prepared on one side of the quantum dot element.

Optionally, said providing a quantum dot material that is quenched by fluorescence includes the steps of: chemically synthesizing quantum dots; using solvents and antisolvents to centrifuge and purify the synthesized quantum dot colloid to remove excess long-chain ligands; The quantum dot colloid purified by centrifugation is dispersed in an organic solvent to obtain a quantum dot solution; the concentration of the quantum dot solution is adjusted to about 10 mg/mL;

Add small molecules or metal ions that can quench the fluorescence of the quantum dots into the quantum dot solution; centrifuge to remove excess ions or small molecules in the quantum dot solution, and then purify them by centrifugation and quench the fluorescence. The quantum dot material is dispersed in the solvent; surfactant is added to prevent a large amount of aggregation when the fluorescence quenched quantum dot material is prepared into powder, and to ensure that the quantum dot powder is evenly dispersed when mixed with the substrate.

In a third aspect, an embodiment of the present disclosure also provides a liquid crystal display panel, including the backlight module described in the first aspect.

In a fourth aspect, an embodiment of the present disclosure also provides a liquid crystal display panel, including a backlight module prepared by the preparation method described in the second aspect.

beneficial effects

The backlight module provided by the embodiment of the present disclosure uses a quantum dot element containing a fluorescence quenched quantum dot material in conjunction with an LED light source, taking advantage of the characteristics of the fluorescence quenched quantum dots to absorb light but not emit light, as well as the adjustable absorption band. , absorbing the light in the crosstalk band, thereby improving the color gamut and making the display better; in addition, compared with luminescent quantum dot materials, quantum dot materials quenched by fluorescence have high stability, low reliability process requirements and low cost The advantages.

Description of the drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings needed to be used in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present disclosure. For those skilled in the art, other drawings can also be obtained based on these drawings without exerting creative efforts.

FIG. 1 is a schematic cross-sectional structural diagram of a backlight module provided by an embodiment of the present disclosure.

FIG. 2 is a schematic cross-sectional structural diagram of a backlight module provided by another embodiment of the present disclosure.

FIG. 3 is a schematic cross-sectional structural diagram of a backlight module provided by yet another embodiment of the present disclosure.

Figure 4 is a schematic diagram of the LED backlight spectrum and the RGB (red, green and blue) three color transmission bands of the LCD screen in an embodiment of the present disclosure.

Figure 5 is a schematic cross-sectional structural diagram of a quantum dot film provided by an embodiment of the present disclosure.

FIG. 6 is a schematic flowchart of a method for manufacturing a backlight module according to an embodiment of the present disclosure.

Reference signs:

11-LED light source; 12-Quantum dot diffusion plate; 13-Lower brightness enhancement sheet: 14-Composite film; 15-Diffusion plate; 16-Quantum dot film; 161-PET layer; 162-Quantum dot adhesive layer; 17-Quantum dots Coating; 10-backlight module; 20-LCD; 100-LCD panel.

Embodiments of the invention

The technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only some of the embodiments of the present disclosure, rather than all of the embodiments. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without making creative efforts fall within the scope of protection of this disclosure.

In the description of the present disclosure, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", " The directions or positional relationships indicated by "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. are based on the directions shown in the accompanying drawings or positional relationships are only for the convenience of describing the present disclosure and simplifying the description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present disclosure. In addition, the terms “first” and “second” are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of indicated technical features. Thus, features defined as “first” and “second” may explicitly or implicitly include one or more of the described features. In the description of the present disclosure, "plurality" means two or more than two, unless otherwise expressly and specifically limited.

"A and/or B" includes the following three combinations: A only, B only, and a combination of A and B.

The use of "suitable for" or "configured to" in this disclosure means open and inclusive language that does not exclude devices that are suitable for or configured to perform additional tasks or steps. Additionally, the use of "based on" is meant to be open and inclusive in that a process, step, calculation or other action "based on" one or more stated conditions or values may in practice be based on additional conditions or beyond the stated values.

In this disclosure, the word "exemplary" is used to mean "serving as an example, illustration, or illustration." Any embodiment described as "exemplary" in this disclosure is not necessarily to be construed as preferred or advantageous over other embodiments. The following description is presented to enable any person skilled in the art to make and use the present disclosure. In the following description, details are set forth for the purpose of explanation. It will be understood that one of ordinary skill in the art will recognize that the present disclosure may be practiced without these specific details. In other instances, well-known structures and processes have not been described in detail to avoid obscuring the disclosure with unnecessary detail. Thus, the present disclosure is not intended to be limited to the embodiments shown but is to be accorded the widest scope consistent with the disclosed principles and features.

Embodiments of the present disclosure provide a backlight module, a preparation method thereof, and a liquid crystal display panel. Each is explained in detail below. It should be noted that the order of description of the following embodiments does not limit the preferred order of the embodiments. In addition, in the description of the present disclosure, the term "including" means "including but not limited to." Various embodiments of the present disclosure may exist in the form of a range; it should be understood that the description in the form of a range is only for convenience and simplicity and should not be understood as a hard limit to the scope of the present disclosure; therefore, the described range should be considered The description has specifically disclosed all possible subranges as well as the single numerical values within that range. Whenever a numerical range is stated herein, it is intended to include any cited number (fractional or whole) within the indicated range.

The inventor found that the traditional LED light source is generally a blue light chip plus red phosphor and green phosphor. The half-peak width of the emission spectrum of green phosphor and red phosphor is wider, which will cause red-green and blue-green crosstalk. It seriously affects the color gamut, thereby affecting the display effect. Luminescent quantum dot materials can achieve a higher color gamut and can be used in quantum dot backlight modules. The structure of the quantum dot backlight module is mainly quantum dot film or quantum dot diffusion plate plus blue LED. However, the cost of quantum dot film is high, the reliability process requirements of quantum dot diffusion plate are high, and the luminescent quantum dot material will also change over time. The luminous efficiency will gradually decrease over time. Once the luminescent quantum dot material fails, the entire LCD panel will not be able to display images normally.

In view of this, first of all, please refer to FIGS. 1 to 3 . An embodiment of the present disclosure provides a backlight module 10 including: a quantum dot element and an LED light source 11 disposed on one side of the quantum dot element; wherein, the quantum dot element The material of the dot element includes quantum dot material that is quenched by fluorescence.

The backlight module 10 provided by the embodiment of the present disclosure uses a quantum dot element containing a fluorescence quenched quantum dot material in conjunction with an LED light source 11, taking advantage of the characteristics of fluorescence quenched quantum dots to absorb light but not emit light, and the adjustable absorption band. characteristics, absorbing light in the crosstalk band, thereby improving the color gamut and making the display better; in addition, because the light-absorbing performance of quantum dots has a longer life than the luminescent performance, compared with luminescent quantum dot materials, fluorescent Quenched quantum dot materials have the advantages of high stability, low reliability process requirements and low cost.

In some embodiments, the characteristic absorption peak of the fluorescence-quenched quantum dot material is 480~520nm, such as 480~485nm, 480~490nm, 480~495nm, 480~500nm, 480~505nm, 480~510nm, 480~515nm, 480~520nm, etc. As shown in Figure 4, because the color gamut of the existing LED light source 11 is mainly affected by the blue-green crosstalk band, and the blue-green crosstalk band range is 480~520nm, in order to obtain a better effect of improving the color gamut. Setting the characteristic absorption peak of the fluorescence-quenched quantum dot material in the range of 480 to 520 nm can improve the problem of blue-green crosstalk and better improve the color gamut. On the other hand, the embodiments of the present disclosure use fluorescence The quenched quantum dot material absorbs the blue-green crosstalk light and can also relatively reduce the intensity of blue light to achieve the purpose of eye protection.

It should be noted that quantum dots of the same material have different band gaps with different sizes. Fluorescence quenching is to reduce the fluorescence efficiency of the quantum dot material and maintain the light absorption performance. Changing the absorption band can be achieved by methods known in the art, such as by adjusting The size of the quantum dot material is achieved, and the specific size is not limited here.

In some embodiments, the backlight module 10 may be a direct-type backlight module or an edge-type backlight module. The quantum dot element may be a quantum dot film 16, a quantum dot diffusion plate 12 or a quantum dot coating 17. For example:

For example, as shown in FIG. 1 , the backlight module 10 is a direct backlight module, and the LED light sources 11 are distributed in an array. The quantum dot element is a quantum dot diffusion plate 12 , and the quantum dot diffusion plate 12 is opposite to the light emitting surface of the LED light source 11 . The backlight module also includes a lower brightness enhancement sheet 13 and a composite film 14 above the quantum dot diffusion plate 12 .

For example, as shown in Figures 2 and 3, the backlight module 10 is a direct-type backlight module, and the LED light sources 11 are distributed in an array. The backlight module 10 also includes a diffusion plate 15. The diffusion plate 15 is opposite to the light-emitting surface of the LED light source 11; wherein, the quantum dot element is a quantum dot film 16 or a quantum dot coating 17, and the quantum dot film 16 or the quantum dot coating 17 is disposed away from the diffusion plate. One side of the LED light source 11. The backlight module also includes a lower brightness enhancement sheet 13 and a composite film 14 above the quantum dot diffusion plate 12 .

For example, the backlight module is an edge-type backlight module (not shown). The backlight module further includes a light guide plate provided on one side of the quantum dot element and an LED provided on the end surface of the light guide plate. A light bar, the LED light source is provided on the LED light bar; the quantum dot element is a quantum dot film or a quantum dot coating.

In some embodiments, as shown in Figure 5, the quantum dot film 16 includes a quantum dot adhesive layer 162 and a PET (polyethylene terephthalate) layer 161 coated on the upper and lower surfaces of the quantum dot adhesive layer, The material of the quantum dot glue layer 162 includes: quantum dot material and colloid that are quenched by fluorescence. Compared with luminescent quantum dot materials, quantum dot materials quenched by fluorescence have a higher lifespan. Therefore, the quantum dot film 16 in the embodiment of the present disclosure does not need to use a barrier film to improve the reliability of the film, that is, a PET layer. Silicon oxide plating is not required. Therefore, when the quantum dot element is the quantum dot film 16, the backlight module 10 provided by the embodiment of the present disclosure also has the advantage of low cost.

In some embodiments, the thickness of the quantum dot glue layer 162 is 40~100 μm, the thickness of the PET layer is 60~120 μm, and the total thickness of the quantum dot film 16 is 180~320 μm. Within this thickness range, the quantum dot film 16 has a better effect of improving the color gamut.

In some embodiments, the material of the quantum dot diffusion plate 12 includes but is not limited to: quantum dot materials that are quenched by fluorescence and light-transmitting plastics, and the light-transmitting plastics include at least one of PS, PC or PMMA.

In some embodiments, the quantum dot diffusion plate 12 can be a single layer or multiple layers, such as three layers. When the quantum dot diffusion plate 12 is a single layer, the material of the quantum dot diffusion plate 12 It is a uniform mixture of fluorescence-quenched quantum dot materials and light-transmitting plastics. When the quantum dot diffusion plate 12 is multi-layered, the structure of the quantum dot diffusion plate 12 is an upper and lower light-transmitting plastic layer and a film layer made of a quantum dot material solution in the middle. In some specific embodiments, the thickness of the upper and lower layers is 200~500 μm, and the total thickness is 1.5~3.0 mm. Within this thickness range, the quantum dot diffusion plate 12 has a better effect of improving the color gamut.

In some embodiments, the quantum dot coating 17 includes, but is not limited to: fluorescence quenched quantum dot materials and colloids. In some specific embodiments, the colloid is acrylic resin.

In some embodiments, the LED light source 11 includes a blue light chip, red phosphor and green phosphor; the red phosphor is selected from YAGA and/or New Red Powder, and the green phosphor is selected from β-SIAION and/or Nitride phosphor. When the phosphors of the LED light source 11 are selected from green phosphors and red YAGA powders, compared with other phosphors, the half-peak width of the emission spectrum of these phosphors is wider. Therefore, when selecting these phosphors, the use of The fluorescence quenched quantum dot material absorbs part of the crosstalk band, narrows the half-peak width, and improves the color gamut and display effect even more significantly. When the red phosphor is a new red powder, matching the fluorescence quenched quantum dot material with the new red powder can achieve the same display effect of improved color gamut as the new red powder with a low-concentration luminescent quantum dot material diffusion plate.

In some embodiments, in order to avoid the problem of red shift of the wavelength after a part of the half-peak width of green light is absorbed and narrowed. The emission wavelength of the green phosphor is 490~600nm, and in particular, the main emission peak is 529nm. After adjusting the green phosphor emission wavelength, the emission color gamut can be greater than or equal to 93%. It should be noted that the emission wavelength can be adjusted by methods known in the art, such as adjusting the element ratio of the phosphor, which is not specifically limited here.

In some embodiments, the fluorescence-quenched quantum dot material is treated with a quencher, and the quencher is selected from but not limited to small molecules or metal ions, such as Fe ³⁺ , Co ²⁺ , Ag ⁺ , At least one of o-nitrophenol and chlorogenic acid. The quantum dots in the fluorescence quenched quantum dot material are selected from, but are not limited to, at least one of CdSe, CdTe, InP, silicon quantum dots or graphene quantum dots.

An embodiment of the present disclosure also provides a method for preparing a backlight module, as shown in Figure 6, including the steps:

S10. Provide quantum dot materials that are quenched by fluorescence;

S20. Make the fluorescence-quenched quantum dot material into a quantum dot element; and

S30. Prepare an LED light source on one side of the quantum dot component.

In the step S10, providing the quantum dot material quenched by fluorescence includes the steps:

(1) Use chemical methods to synthesize quantum dots, such as CdSe, CdTe, InP, silicon quantum dots, and graphene quantum dots.

(2) Use solvents and antisolvents to centrifuge the synthesized quantum dot colloid to remove excess long-chain ligands. Centrifuge 3 to 5 times to remove as much excess long-chain ligands as possible.

(3) Disperse the centrifugally purified quantum dot colloid in an organic solvent to obtain a quantum dot solution. The organic solvent can be selected from at least one of chloroform, toluene, cyclohexane, n-octane and carbon tetrachloride.

(4) Adjust the concentration of the quantum dot solution to approximately 10 mg/mL (milligrams per milliliter) to ensure that subsequent surface treatment is more complete.

(5) Add small molecules or metal ions that can quench the fluorescence of quantum dots, such as at least one of Fe ³⁺ , Co ²⁺ , Ag ⁺ , o-nitrophenol, and chlorogenic acid.

(6) Centrifuge to remove excess ions or small molecules in the solution, and then disperse the centrifuged-purified fluorescence-quenched quantum dot material in the solvent.

(7) Add surfactant to prevent large amounts of aggregation when the fluorescence-quenched quantum dot material is prepared into powder, and ensure that the quantum dot powder is evenly dispersed when mixed with the substrate.

In step S20, making the fluorescence quenched quantum dot material into a quantum dot element includes the step of: making the fluorescence quenched quantum dot material into a quantum dot element, and the quantum dot element can specifically be made into a quantum dot. In the form of diffusion plates, quantum dot films or quantum dot coatings.

It should be noted that the quantum dot diffusion plate, quantum dot film or quantum dot coating can be prepared using methods known in the art. For example, in some embodiments, the quantum dot film can use a coating machine to combine a quantum dot solution with acrylic acid. The system is prepared by mixing glue. In particular, the mass ratio of quantum dot solution to glue is (1~2):20, for example: 1:20, 1.1:20, 1.2:20, 1.3:20, 1.4:20, 1.5:20, 1.6:20, 1.7:20, 1.8:20, 1.9:20, 2:20, etc. The mass concentration of the quantum dot solution is 5% to 10%, such as 5%, 6%, 7%, 8%, 9%, 10%, etc. Within this density range, the color gamut improvement effect is better.

Correspondingly, the present disclosure also provides a liquid crystal display panel, including the backlight module provided in any of the above embodiments.

For example, as shown in FIG. 1 , the liquid crystal display panel 100 includes a backlight module 10 and an LCD 20 above the backlight module 10 . The backlight module 10 includes: an LED light source 11, a quantum dot diffusion plate 12, a lower brightness enhancement sheet 13, and a composite film 14 stacked in sequence from bottom to top. As shown in FIG. 2 , the liquid crystal display panel 100 includes a backlight module 10 and an LCD 20 above the backlight module 10 . The backlight module 10 includes, stacked from bottom to top: an LED light source 11, a diffusion plate 15, a quantum dot film 16, a lower brightness enhancement sheet 13, and a composite film 14.

For example, as shown in FIG. 2 , the liquid crystal display panel 100 includes a backlight module 10 and an LCD 20 above the backlight module 10 . The backlight module 10 includes, stacked from bottom to top: an LED light source 11, a diffusion plate 15, a quantum dot film 16, a lower brightness enhancement sheet 13, and a composite film 14.

For example, as shown in FIG. 3 , the liquid crystal display panel 100 includes a backlight module 10 and an LCD 20 above the backlight module 10 . The backlight module 10 includes stacked from bottom to top: LED light source 11, diffusion plate 15, quantum dot coating 17, lower brightness enhancement sheet 13, and composite film 14.

The LCD 20 includes an array substrate and a counter substrate (not shown), which are opposed to each other to form a liquid crystal cell, and the liquid crystal cell is filled with liquid crystal material. The opposite substrate is, for example, a color filter substrate. The pixel electrode of each sub-pixel unit of the array substrate is used to apply an electric field to control the degree of rotation of the liquid crystal material to perform display operations.

The following is specifically explained in combination with experiments. The following examples are only exemplary embodiments of the present invention and do not limit the present invention.

Example 1

As shown in FIG. 1 , this embodiment provides a method for preparing a backlight module and a quantum dot element. The backlight module includes an LED light source, a quantum dot diffusion plate, a lower brightness enhancement sheet, and a composite film stacked in sequence from bottom to top. Among them, the red light of the backlight uses new red powder, and the green light uses 529nm green phosphor.

The quantum dot element is a diffusion plate made of CdSe system quantum dot material that has been treated with a quencher for fluorescence quenching. The preparation method includes: mixing the quantum dot material solution and PS particles evenly and using an extruder to co-extrude the upper and lower layers. The first layer is PS, and the middle layer is a mixed layer of PS and quantum dot material. It can also be a single-layer basis. This embodiment is a three-layer extrusion. Parameters: The total thickness of the upper and lower layers of the three layers is 400μm, the middle layer is 700μm, and the total thickness is 1.5mm.

Use CR 250 (spectral radiometer) to test the color point after passing through the screen. The color point after passing through the screen is X=0.28, Y=0.29, and the color gamut after passing through the screen: DCIP3=93.8%.

Example 2

As shown in Figure 2, this embodiment provides a method for preparing a backlight module and a quantum dot element. The backlight module includes stacked from bottom to top: LED light source, diffusion plate, quantum dot film, lower brightness enhancement sheet, composite membrane.

The quantum dot element is a quantum dot film prepared from a CdSe system quantum dot material that has undergone fluorescence quenching treatment with a quencher. The quantum dot film has three layers, including a quantum dot glue layer and PET coated on the upper and lower surfaces of the quantum dot glue layer. . The preparation method includes: using a film coating machine to mix a quantum dot solution and an acrylic system glue to prepare a quantum dot glue layer, where the mass ratio of the quantum dot solution to the glue is 1:20, and the mass concentration of the quantum dot solution is 7%. The thickness of the glue layer is 60μm, the thickness of PET is 60μm, and the total thickness of the film is 180μm.

Use CR 250 to test the color point after passing through the screen. The color point after passing through the screen is X=0.28, Y=0.29, and the color gamut after passing through the screen: DCIP3=94%.

Example 3

As shown in Figure 3, this embodiment provides a method for preparing a backlight module and a quantum dot element. The backlight module includes stacked from bottom to top: LED light source, diffusion plate, quantum dot coating, lower brightness enhancement sheet, Composite membrane.

The quantum dot element is a quantum dot coating prepared from a CdSe system quantum dot material that has undergone fluorescence quenching treatment with a quencher. The glue ratio and quantum dot concentration of the coating are the same as those in Example 2.

Use CR 250 to test the cross-screen color gamut: DCIP3=93.7%

Comparative ratio

The basic structure of the comparative example is the same as that of Example 1. The only difference is that there is no quantum dot material that has been fluorescence quenched by the quencher in the diffusion plate. The cross-screen color gamut of the diffusion plate is DCIP3=92% when tested with CR 250.

According to the above results, it can be seen that the cross-screen color gamut of Examples 1 to 3 is higher than that of the comparative example. For example, the cross-screen color gamut of Example 1 is 93.8%, and the cross-screen color gamut of the comparative example is 93.8%. is 92%. It shows that using quantum dot components containing fluorescence-quenched quantum dot materials with LED light sources can improve the color gamut and make the display better. This is due to the fact that fluorescence quenched quantum dots can absorb light in the crosstalk band.

The backlight module, its preparation method, and the liquid crystal display panel provided by the embodiments of the present disclosure have been introduced in detail. This article uses specific examples to illustrate the principles and implementation methods of the present disclosure. The description of the above embodiments is only for It helps to understand the methods and core ideas of the present disclosure; at the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present disclosure. In summary, the content of this specification does not It should be understood as a limitation of this disclosure.

Claims (20)

A backlight module includes: a quantum dot element and an LED light source provided on one side of the quantum dot element; wherein the material of the quantum dot element includes a quantum dot material that is quenched by fluorescence. The backlight module of claim 1, wherein the characteristic absorption peak of the fluorescence-quenched quantum dot material is 480 to 520 nm. The backlight module of claim 1, wherein the quantum dot element is a quantum dot film, a quantum dot diffusion plate or a quantum dot coating. The backlight module according to claim 3, wherein the backlight module is a direct backlight module, and the LED light sources are distributed in an array; wherein the quantum dot elements are quantum dot diffusion plates, and the quantum dots The diffusion plate is opposite to the light exit surface of the LED light source. The backlight module according to claim 3, wherein the backlight module is a direct-type backlight module, the LED light sources are distributed in an array, the backlight module further includes a diffusion plate, the diffusion plate and the The light-emitting surfaces of the LED light sources are opposite; wherein, the quantum dot element is a quantum dot film or a quantum dot coating, and the quantum dot film or quantum dot coating is provided on the side of the diffusion plate away from the LED light source. The backlight module according to claim 3, wherein the backlight module is an edge-type backlight module, and the backlight module further includes a light guide plate provided on one side of the quantum dot element and a light guide plate provided on one side of the quantum dot element. An LED light bar on the end face of the light guide plate, the LED light source is provided on the LED light bar; wherein the quantum dot element is a quantum dot film or a quantum dot coating. The backlight module of claim 3, wherein the quantum dot film includes: a quantum dot glue layer and a PET layer coated on the upper and lower surfaces of the quantum dot glue layer; the material of the quantum dot glue layer includes: the Quantum dot materials and colloids that are quenched by fluorescence. The backlight module according to claim 7, wherein the thickness of the quantum dot glue layer is 40~100 μm, the thickness of the PET layer is 60~120 μm, and the total thickness of the quantum dot film is 180~320 μm. The backlight module according to claim 3, wherein the material of the quantum dot diffusion plate includes: the quantum dot material quenched by fluorescence and light-transmitting plastic; the light-transmitting plastic includes PS, PC or PMMA. of at least one. The backlight module according to claim 9, wherein the quantum dot diffusion plate is a single layer, and the material of the quantum dot diffusion plate is uniformly mixed quantum dot material quenched by fluorescence and light-transmitting plastic. The backlight module according to claim 9, wherein the quantum dot diffusion plate is multi-layered, and the structure of the quantum dot diffusion plate is made of an upper and lower light-transmitting plastic layer and a quantum dot material solution in the middle. film layer. The backlight module of claim 3, wherein the quantum dot coating includes: the fluorescence quenched quantum dot material and colloid. The backlight module according to claim 1, wherein the LED light source includes a blue light chip, red phosphor and green phosphor; the red phosphor is selected from YAGA and/or New Red Powder, and the green phosphor is selected from β-SIAION and/or nitride phosphor. The backlight module according to claim 13, wherein the emission wavelength of the green phosphor is 490~600 nm. The backlight module of claim 1, wherein the fluorescence-quenched quantum dot material is treated with a quencher, and the quencher is selected from Fe ³⁺ , Co ²⁺ , Ag ⁺ , o-nitro At least one of phenol and chlorogenic acid. The backlight module of claim 1, wherein the quantum dots are selected from at least one of CdSe, CdTe, InP, silicon quantum dots or graphene quantum dots. A method for preparing a backlight module, including the steps: Provide quantum dot materials that are quenched by fluorescence; Making the fluorescence quenched quantum dot material into a quantum dot element; and An LED light source is prepared on one side of the quantum dot element. The method for preparing a backlight module according to claim 17, said providing a quantum dot material quenched by fluorescence, including the steps of: Using chemical methods to synthesize quantum dots; Use solvents and antisolvents to centrifuge the synthesized quantum dot colloids to remove excess long-chain ligands; The quantum dot colloid purified by centrifugation is dispersed in an organic solvent to obtain a quantum dot solution; Adjust the concentration of the quantum dot solution to approximately 10 mg/mL; Adding small molecules or metal ions that can quench the fluorescence of the quantum dots into the quantum dot solution; Centrifuge to remove excess ions or small molecules in the quantum dot solution, and then disperse the centrifugally purified and fluorescence-quenched quantum dot material in the solvent; Adding surfactant prevents large amounts of aggregation when the fluorescence-quenched quantum dot material is prepared into powder, and ensures that the quantum dot powder is evenly dispersed when mixed with the substrate. A liquid crystal display panel comprising the backlight module according to any one of claims 1 to 16. A liquid crystal display panel, including a backlight module prepared by the preparation method described in claim 17 or 18.