Liquid crystal bragg brightening antireflection polarizer, method of manufacturing the same, and electronic device

Abstract

The application provides a liquid crystal Bragg brightening and antireflection polarizer, a preparation method thereof and electronic equipment, which can transmit one linearly polarized light and reflect another linearly polarized light without stacking a wideband quarter-wave plate, so as to play a role of brightening and antireflection in a liquid crystal display backlight module, and is beneficial to reducing the cost of the module. The liquid crystal Bragg brightening and antireflection polarizer comprises: an alignment unit; and a plurality of Bragg structure units which are sequentially stacked on one side of the alignment unit; wherein each Bragg structure unit comprises a first nematic liquid crystal layer and a second nematic liquid crystal layer which are stacked with each other, and the extraordinary light refractive index and thickness of the first nematic liquid crystal layer are different from those of the second nematic liquid crystal layer, for transmitting a first linearly polarized light and reflecting a second linearly polarized light which is perpendicular to the polarization direction of the first linearly polarized light.

Description

Technical Field

[0001] This application relates to the field of polarization technology, and in particular to a liquid crystal Bragg brightening and transmission enhancing polarizer, its preparation method, and electronic equipment. Background Technology

[0002] DBEF (Dual Brightness Enhancement Film), a type of brightness enhancement film made from traditional polymer materials, is mainly used in the backlight modules of liquid crystal displays. It can recycle polarized light that cannot be transmitted, thereby improving brightness and light utilization. For example... Figure 1 As shown, in existing LCD backlight modules: if a DBEF film is not installed (such as...) Figure 1 In the left part of the image, when P-polarized light (hereinafter referred to as P light) and S-polarized light (hereinafter referred to as S light) emitted from the LCD (Liquid Crystal Display) backlight shine on the lower polarizer of the LCD panel, only P light can be transmitted, while S light is usually absorbed and lost by the lower polarizer; if a DBEF film (such as...) is set... Figure 1 (In the right part of the image), when the P-light and S-light emitted by the LCD backlight illuminate the DBEF film, the P-light can be directly transmitted, while the S-light is usually reflected back into the interior of the LCD backlight by the DBEF film. It is first scattered by the diffuser of the LCD backlight to be partially converted into P-light, and then reflected back to the DBEF film by the reflector of the LCD backlight. This increases the amount of P-light that passes through the DBEF film to reach the LCD panel, thereby enhancing the brightness and light utilization.

[0003] With the continuous advancement of science and technology, people are also trying to use liquid crystal materials to make brightness enhancement films to replace DBEF films. However, existing liquid crystal brightness enhancement films usually utilize the Bragg reflection effect of cholesteric liquid crystal (CLC), but because it reflects circularly polarized light, an additional broadband quarter-wave plate needs to be superimposed before it can be applied to the backlight module of liquid crystal display, making it difficult to control the module cost. Summary of the Invention

[0004] One advantage of this application is that it provides a liquid crystal Bragg brightening and transmission enhancement polarizer, its preparation method and electronic device, which can transmit one type of linearly polarized light and reflect another type of linearly polarized light without superimposing a broadband quarter-wave plate, so as to achieve the effect of enhancing transmission and brightness in the liquid crystal display backlight module, which is beneficial to reducing the module cost.

[0005] Another advantage of this application is that it provides a liquid crystal Bragg brightening and transmission enhancing polarizer, its preparation method and electronic device. In one embodiment of this application, the liquid crystal Bragg brightening and transmission enhancing polarizer only requires the liquid crystal to be in a normal nematic phase, rather than in a complex smectic layered phase, which helps to significantly reduce the difficulty of the process and reduce costs.

[0006] Another advantage of this application is that it provides a liquid crystal Bragg brightness enhancement and transmission enhancement polarizer, its preparation method and electronic device. In one embodiment of this application, the liquid crystal Bragg brightness enhancement and transmission enhancement polarizer can be used not only with traditional linear polarizers, but also with interference liquid crystal polarizers, both of which can achieve the required transmission enhancement and brightness enhancement effect in liquid crystal display backlight modules.

[0007] Another advantage of this application is that it provides a liquid crystal Bragg brightening and brightening polarizer, its preparation method and electronic device. In one embodiment of this application, the liquid crystal Bragg brightening and brightening polarizer does not require a co-extrusion stretching process of hundreds or thousands of polymer materials like DBEF films. It can be directly and simply printed and stacked with raised parts, which helps to reduce the manufacturing difficulty and cost.

[0008] Another advantage of this application is that it provides a liquid crystal Bragg brightening and transmission enhancement polarizer, its preparation method and electronic device. In one embodiment of this application, the liquid crystal Bragg brightening and transmission enhancement polarizer can be directly fused with the interference liquid crystal polarizer, which is simple and effective in structure and helps to reduce manufacturing costs.

[0009] Another advantage of this application is that it provides a liquid crystal Bragg brightness-enhancing and transmission-enhancing polarizer, its preparation method, and an electronic device thereof, wherein expensive materials or complex structures are not required to achieve the above objectives. Therefore, this application successfully and effectively provides a solution that not only provides a simple liquid crystal Bragg brightness-enhancing and transmission-enhancing polarizer, its preparation method, and the electronic device thereof, but also increases the practicality and reliability of the liquid crystal Bragg brightness-enhancing and transmission-enhancing polarizer, its preparation method, and the electronic device thereof.

[0010] To achieve at least one of the above advantages or other benefits and objectives of this application, some embodiments of this application provide a liquid crystal Bragg brightening and transmission enhancing polarizer, comprising: an alignment unit; and a plurality of Bragg structure units, which are sequentially stacked on one side of the alignment unit; wherein each of the Bragg structure units includes a first nematic liquid crystal layer and a second nematic liquid crystal layer stacked on top of each other, and the unusual light refractive index and thickness of the first nematic liquid crystal layer are different from the unusual light refractive index and thickness of the second nematic liquid crystal layer, for transmitting first linearly polarized light and reflecting second linearly polarized light perpendicular to the polarization direction of the first linearly polarized light.

[0011] In some embodiments of this application, each of the Bragg structural units satisfies the relation: n e1 ×d1=n e2 ×d2=λ / 4; where: n e1 d1 is the unusual optical refractive index of the first nematic liquid crystal layer, and n is the thickness of the first nematic liquid crystal layer; e2 d2 is the unusual light refractive index of the second nematic liquid crystal layer, d2 is the thickness of the second nematic liquid crystal layer, and λ is the reflection center wavelength of the Bragg structure unit.

[0012] In some embodiments of this application, the plurality of Bragg structural units have different thicknesses.

[0013] In some embodiments of this application, the thickness of the Bragg structural unit increases or decreases sequentially along the direction away from the alignment unit.

[0014] In some embodiments of this application, the relative difference in unusual optical refractive index between the first nematic liquid crystal layer and the second nematic liquid crystal layer in each Bragg structure unit is greater than or equal to 20%.

[0015] In some embodiments of this application, the unusual light refractive index of the first nematic liquid crystal layer is 1.5; and the unusual light refractive index of the second nematic liquid crystal layer is 2.0.

[0016] In some embodiments of this application, the liquid crystal Bragg brightening and transmission enhancing polarizer further includes a plurality of liquid crystal dye layers; wherein the plurality of liquid crystal dye layers are stacked sequentially on the Bragg structure unit, and each liquid crystal dye layer is formed by coating a mixture of polymerizable nematic liquid crystal and dichroic dye.

[0017] In some embodiments of this application, along a direction away from the liquid crystal Bragg brightening and brightening polarizer, the ratio of the polymerizable nematic liquid crystal and the dichroic dye in the liquid crystal dye layer alternates between high and low.

[0018] According to another aspect of this application, this application further provides an electronic device, including: a backlight; a display panel; and a liquid crystal Bragg brightening and transmission enhancing polarizer as described in any of the preceding claims, disposed between the backlight and the display panel, for transmitting second linearly polarized light from the backlight to propagate to the display panel, and reflecting first linearly polarized light from the backlight to propagate back to the backlight.

[0019] In some embodiments of this application, the display panel includes a liquid crystal panel, a first polarizer stacked on the liquid crystal panel facing the side of the liquid crystal Bragg brightening and brightening polarizer, and a second polarizer stacked on the liquid crystal panel facing away from the liquid crystal Bragg brightening and brightening polarizer.

[0020] In some embodiments of this application, the first polarizing element is a conventional linear polarizer, a conventional liquid crystal polarizer, or an interference-type liquid crystal polarizer.

[0021] In some embodiments of this application, the display panel includes a liquid crystal panel and a second polarizer stacked on the liquid crystal panel on the side facing away from the backlight source; and the alignment unit of the liquid crystal Bragg brightening and transmission enhancing polarizer is arranged facing the backlight source.

[0022] According to another aspect of this application, this application further provides a method for preparing a liquid crystal Bragg brightening and transmission enhancing polarizer, comprising the steps of: Different nematic liquid crystal monomers are dissolved in a solvent to obtain at least two liquid crystal coating solutions; Different liquid crystal coating liquids are sequentially and alternately coated on one side of the alignment unit to form a plurality of Bragg structure units that are sequentially stacked on the alignment unit, such that each Bragg structure unit includes a first nematic liquid crystal layer and a second nematic liquid crystal layer that have different unusual light refractive indices and thicknesses and are stacked on each other.

[0023] In some embodiments of this application, the method for preparing the liquid crystal Bragg brightening and transmission enhancing polarizer further includes the step of: Mix polymerizable nematic liquid crystal and dichroic dye according to a preset ratio to obtain at least two liquid crystal dye mixtures with different ratios; Different liquid crystal dye mixtures are sequentially and alternately coated on the Bragg structure unit to form multiple liquid crystal dye layers that are sequentially stacked on the Bragg structure unit, such that the ratio between polymerizable nematic liquid crystal and dichroic dye in the liquid crystal dye layer alternates between high and low. Attached Figure Description

[0024] Figure 1 This is a schematic diagram illustrating the brightness enhancement principle of existing LCD backlight modules using DBEF films. Figure 2 This is a schematic diagram of the structure of an electronic device according to an embodiment of this application; Figure 3 A schematic diagram illustrating the brightness enhancement principle of an electronic device according to the above embodiments of this application is shown; Figure 4 A schematic diagram of the structure of a liquid crystal Bragg brightening and transmission-enhancing polarizer in an electronic device according to the above embodiments of this application is shown; Figure 5 An example of the reflection band of a single Bragg structure unit in a liquid crystal Bragg brightening and transmission enhancing polarizer according to the above embodiments of this application is shown; Figure 6 Another example of the reflection band of a single Bragg structure unit in a liquid crystal Bragg brightening and transmission enhancing polarizer according to the above embodiments of this application is shown; Figure 7 An example of an interferometric liquid crystal polarizer in an electronic device according to the above embodiments of this application is shown; Figure 8 A modified embodiment of the electronic device according to the above embodiments of this application is shown; Figure 9 A schematic diagram of the structure of a liquid crystal Bragg brightening and transmission-enhancing polarizer in an electronic device according to the above-described modified embodiments of this application is shown; Figure 10 This is a schematic flowchart illustrating a method for preparing a liquid crystal Bragg brightening and transmission enhancing polarizer according to an embodiment of this application.

[0025] Explanation of key component symbols: 10. Backlight; 11. Reflector; 12. Light guide; 13. Light-emitting element; 14. Diffuser; 20. Display panel; 21. Liquid crystal panel; 22. First polarizer; 220. Interferometric liquid crystal polarizer; 221. Alignment substrate; 222. Liquid crystal dye layer; 2221. Convergent nematic liquid crystal; 2222. Dichroic dye; 23. Second polarizer; 30. Liquid crystal Bragg brightening and transmission enhancing polarizer; 31. Alignment unit; 32. Bragg structure unit; 321. First nematic liquid crystal layer; 322. Second nematic liquid crystal layer.

[0026] The above description of the main component symbols, together with the accompanying drawings and specific embodiments, provides a further detailed explanation of this application. Detailed Implementation

[0027] The following description is intended to disclose this application and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art. The basic principles of this application defined in the following description can be applied to other embodiments, modifications, improvements, equivalents, and other technical solutions that do not depart from the spirit and scope of this application.

[0028] Those skilled in the art should understand that, in the disclosure of this application, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limitations on this application.

[0029] In this application, the term "a" should be understood as "one or more," meaning that in one embodiment, the number of an element can be one, while in another embodiment, the number of the element can be multiple. Unless explicitly indicated in the disclosure of this application that the number of the element is only one, the term "a" should not be construed as unique or singular, nor should it be construed as a limitation on the quantity.

[0030] In the description of this application, it should be understood that terms such as "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. In the description of this application, it should be noted that, unless otherwise expressly specified and limited, terms such as "connected" or "linked" should be interpreted broadly. For example, it can refer to a fixed connection, a detachable connection, or an integral connection; it can refer to a mechanical connection or an electrical connection; it can refer to a direct connection or an indirect connection through a medium. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0031] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0032] Considering such Figure 1The DBEF film used in existing liquid crystal display backlight modules requires a co-extrusion stretching process of hundreds or thousands of layers of polymer materials, which is difficult and costly to manufacture. Existing liquid crystal polarizers not only require the liquid crystal to be in a layered smectic state before polymerization, but also require an additional broadband quarter-wave plate to be stacked before they can be used in liquid crystal display backlight modules, leading to significant challenges in process control and module cost control. Therefore, this application creatively proposes a liquid crystal Bragg brightening and transmission-enhancing polarizer, its preparation method, and electronic equipment. This polarizer can transmit one type of linearly polarized light and reflect another type of linearly polarized light without stacking a broadband quarter-wave plate, thus achieving a brightening and transmission-enhancing effect in liquid crystal display backlight modules and helping to reduce module costs.

[0033] Specifically, refer to the accompanying drawings in the specification of this application. Figure 2 and Figure 3 According to one embodiment of this application, an electronic device is provided, which may include a backlight 10, a display panel 20, and a liquid crystal Bragg brightness enhancement and transmission enhancement polarizer 30 disposed between the backlight 10 and the display panel 20. The liquid crystal Bragg brightness enhancement and transmission enhancement polarizer 30 is used to transmit first linearly polarized light from the backlight 10 to the display panel 20 and reflect second linearly polarized light from the backlight 10 back to the backlight 10. At the same time, the second linearly polarized light reflected back to the backlight 10 by the liquid crystal Bragg brightness enhancement and transmission enhancement polarizer 30 can be scattered by the backlight 10 to at least partially convert into first linearly polarized light, and reflected back to the liquid crystal Bragg brightness enhancement and transmission enhancement polarizer 30 to pass through the liquid crystal Bragg brightness enhancement and transmission enhancement polarizer 30 and propagate to the display panel 20, which is beneficial to improving brightness and light utilization. It is understood that the polarization direction of the first linearly polarized light mentioned in this application is perpendicular to the polarization direction of the second linearly polarized light. For example, the first linearly polarized light can be implemented as S light or P light, and the second linearly polarized light is implemented as P light or S light accordingly.

[0034] More specifically, such as Figure 3 and Figure 4 As shown, the liquid crystal Bragg brightening and transmission enhancing polarizer 30 may include an alignment unit 31 and a plurality of Bragg structure units 32. The plurality of Bragg structure units 32 are sequentially stacked on one side of the alignment unit 31; wherein each Bragg structure unit 32 includes a first nematic liquid crystal layer 321 and a second nematic liquid crystal layer 322 stacked together, and the unusual light refractive index n of the first nematic liquid crystal layer 321 is... e1 The thickness d1 is different from the unusual optical refractive index n of the second nematic liquid crystal layer 322. e2The thickness d2 is used to transmit first linearly polarized light and reflect second linearly polarized light perpendicular to the polarization direction of the first linearly polarized light. It is understood that the alignment unit 31 mentioned in this application refers to a light-transmitting substrate with an alignment layer, used to control the orientation of liquid crystal molecules in each nematic liquid crystal layer; the first nematic liquid crystal layer 321 and the second nematic liquid crystal layer 322 in each Bragg structure unit 32 can be made of different liquid crystal materials to have different unusual optical refractive indices.

[0035] It is worth noting that the thickness mentioned in this application refers to the dimension of each nematic liquid crystal layer in the stacking direction, that is, the direction corresponding to the alignment layer perpendicular to the alignment unit 31 (or along the direction away from the alignment unit 31), such as Figure 2 The vertical direction is shown. In this way, the first nematic liquid crystal layer 321 and the second nematic liquid crystal layer 322, which have different thicknesses and unusual refractive indices, can together form a Bragg structure to directly transmit one type of linearly polarized light and reflect another type of linearly polarized light without superimposing a broadband quarter-wave plate.

[0036] Furthermore, the unusual optical refractive index n mentioned in this application e This refers to the refractive index of the nematic liquid crystal layer in the direction of light wave vibration parallel to the long axis of the liquid crystal molecules. It corresponds to the polarization direction of the second linearly polarized light, enabling the second linearly polarized light to experience the Bragg structure and undergo Bragg reflection. Meanwhile, the first linearly polarized light, because its polarization direction is perpendicular to the long axis of the liquid crystal molecules, does not experience the Bragg structure and can be directly transmitted.

[0037] In particular, such as Figure 4 As shown, each Bragg structural unit 32 satisfies the following relation: n e1 ×d1=n e2 ×d2=λ / 4; where: n e1 d1 is the unusual optical refractive index of the first nematic liquid crystal layer, and n is the thickness of the first nematic liquid crystal layer; e2 Let d2 be the unusual refractive index of the second nematic liquid crystal layer, d2 be the thickness of the second nematic liquid crystal layer, and λ be the reflection center wavelength of the Bragg structure unit. In this way, the first nematic liquid crystal layer 321 and the second nematic liquid crystal layer 322 can form a perfect Bragg structure, so that by utilizing the light interference effect, the Bragg reflection of the second linearly polarized light at the interface between the first nematic liquid crystal layer 321 and the second nematic liquid crystal layer 322 is maximized, thereby achieving a better anti-reflection and brightening effect. It is understood that in other examples of this application, the unusual refractive index n of each nematic liquid crystal layer... e The product of the thickness d of the nematic liquid crystal layer and the reflection center wavelength can have a small difference from one-quarter of the reflection center wavelength. For example, if the difference is within 20%, the required Bragg reflection effect can still be achieved.

[0038] It is worth noting that, such as Figure 3 and Figure 4 As shown, the multiple Bragg structure units 32 in the liquid crystal Bragg brightening and transmission enhancing polarizer 30 of this application can have different thicknesses, so that each Bragg structure unit 32 can reflect second linearly polarized light with different center wavelengths, thereby realizing broadband reflection and broadband transmission of the liquid crystal Bragg brightening and transmission enhancing polarizer 30 to cover the entire visible light band.

[0039] Furthermore, the reflection bandwidth of each Bragg structure unit 32 depends on the unusual optical refractive index difference between the first nematic liquid crystal layer 321 and the second nematic liquid crystal layer 322; that is, the greater the unusual optical refractive index difference between the first nematic liquid crystal layer 321 and the second nematic liquid crystal layer 322, the wider the reflection bandwidth of the corresponding Bragg structure unit 32. For example, as... Figure 5 As shown, when the unusual light refractive index n of the first nematic liquid crystal layer 321... e1 =1.5, and the unusual light refractive index n of the second nematic liquid crystal layer 322 is 1.5. e2 When the ratio is 1.6, the reflection bandwidth of the Bragg structure unit 32 is basically between 480nm and 520nm; while if Figure 6 As shown, when the unusual light refractive index n of the first nematic liquid crystal layer 321... e1 =1.5, and the unusual light refractive index n of the second nematic liquid crystal layer 322 is 1.5. e2 When the value is 2.0, the reflection bandwidth of the Bragg structure unit 32 is basically between 450nm and 550nm.

[0040] Therefore, in each Bragg structure unit 32 of this application, the relative difference in unusual optical refractive index between the first nematic liquid crystal layer 321 and the second nematic liquid crystal layer 322 is preferably greater than or equal to 20%, so that each Bragg structure unit 32 covers a wider reflection band as much as possible. It is understood that the relative difference mentioned in this application refers to |n e2 -n e1 | / n e1 ×100%.

[0041] Preferably, such as Figure 3 and Figure 4 As shown, along the direction away from the alignment unit 31, the thickness of the Bragg structure unit 32 increases or decreases sequentially, so that the liquid crystal Bragg brightening and transmission enhancing polarizer 30 has a sequentially varying pitch, thereby better realizing the broadband Bragg reflection effect. It is understood that the sequential increase or decrease mentioned in this application can be implemented as a step-like increase or decrease, or as a gradual increase or decrease.

[0042] It is important to note that, such as Figure 3 and Figure 4 As shown, for the unusual optical refractive index n of the first nematic liquid crystal layer 321 e1 =1.5, and the unusual light refractive index n of the second nematic liquid crystal layer 322 is 1.5. e2 For a value of 2.0, it is sufficient to sequentially stack three Bragg structure units 32 of corresponding thickness on the alignment unit 31, so that the three Bragg structure units 32 cover the red, green, and blue wavelength bands respectively, to ensure that the liquid crystal Bragg brightening and anti-transmission polarizer 30 covers the entire visible light band. Of course, in other examples of this application, the liquid crystal Bragg brightening and anti-transmission polarizer 30 can be stacked with more layers of Bragg structure units 32, so that the thickness difference between two adjacent Bragg structure units 32 is reduced, so as to more uniformly cover the entire visible light band and improve the anti-transmission and brightening effect.

[0043] Furthermore, since the thickness d of each nematic liquid crystal layer is basically equal to one-quarter of the reflection center wavelength (i.e., one-quarter of the wavelength of the second linear polarized light), such as 500nm, the thickness d of each nematic liquid crystal layer is in the nanometer range. Therefore, even if the number of stacked nematic liquid crystal layers in the liquid crystal Bragg brightening and brightening polarizer 30 reaches the order of hundreds, the thickness of the liquid crystal Bragg brightening and brightening polarizer 30 is still in the order of several micrometers, maintaining the thickness advantage over traditional polarizers. In other words, the liquid crystal Bragg brightening and brightening polarizer 30 of this application avoids the process difficulty of liquid crystal smectic phases and has the advantage of ultra-thin thickness, making it easy to fold.

[0044] According to the above embodiments of this application, as Figure 2 and Figure 3 As shown, the backlight 10 may include a reflector 11, a light guide 12 stacked between the reflector 11 and the liquid crystal Bragg brightening and brightening polarizer 30, a light-emitting element 13 disposed at the end of the light guide 12, and a light-diffusing element 14 stacked between the reflector 11 and the liquid crystal Bragg brightening and brightening polarizer 30.

[0045] Preferably, such as Figure 2 and Figure 3 As shown, the light-diffusing element 14 is located on the side of the light guide 12 facing away from the reflector 11, so that the light-diffusing element 14 is positioned between the light guide 12 and the liquid crystal Bragg brightening and anti-transmittance polarizer 30. This allows the illumination light emitted by the light-emitting element 13 to first be redirected and propagated through the light guide 12, and then diffused and homogenized by the light-diffusing element 14 before propagating to the liquid crystal Bragg brightening and anti-transmittance polarizer 30. It is understood that in other examples of this application, the light-diffusing element 14 may also be located between the reflector 11 and the light guide 12, which will not be described further in this application.

[0046] It is worth noting that the light guide 12 mentioned in this application may be implemented as an optical waveguide, but is not limited to; the light-emitting element 13 mentioned in this application may be implemented as an LED (Light Emitting Diode), but is not limited to; and the light-diffusing element 14 mentioned in this application may be implemented as a light-diffusing film or a diffuser, etc.

[0047] For example, if the long axis of the liquid crystal molecules in the liquid crystal Bragg brightening and anti-transmittance polarizer 30 is aligned horizontally, then the horizontally polarized component of the illumination light emitted via the backlight 10 (i.e., P-light) is defined as the second linearly polarized light, and the vertically polarized component of the illumination light (i.e., S-light) is defined as the first linearly polarized light. Thus, as... Figure 3 As shown, the S-light in the illumination light emitted by the backlight 10 does not sense the Bragg structure and directly passes through the liquid crystal Bragg brightness enhancement and transmission polarizer 30 to propagate to the display panel 20; at the same time, the P-light in the illumination light emitted by the backlight 10 senses the Bragg structure and is reflected back to the backlight 10, so that this part of the P-light is first scattered by the diffuser 14 of the backlight 10 to at least partially convert into S-light, and then reflected back to the liquid crystal Bragg brightness enhancement and transmission polarizer 30 by the reflector 11 of the backlight 10. The reflected S-light then passes through the liquid crystal Bragg brightness enhancement and transmission polarizer 30 to propagate to the display panel 20, thereby improving light energy utilization and brightness. It is understandable that the P light reflected back by the reflector 11 is reflected back to the backlight 10 by the liquid crystal Bragg brightening and transmission-enhancing polarizer 30. This cycle of reflection and scattering can further improve the light conversion efficiency, so that almost all P light can be converted into S light, ensuring that the brightening efficiency of the liquid crystal Bragg brightening and transmission-enhancing polarizer 30 can be close to 100%.

[0048] Optionally, such as Figure 2 and Figure 3 As shown, the display panel 20 includes a liquid crystal panel 21 and a first polarizer 22 stacked on the liquid crystal panel 21 facing the side of the liquid crystal Bragg brightness enhancement and transmission enhancement polarizer 30. The first polarizer 22 is used to transmit first polarized light from the liquid crystal Bragg brightness enhancement and transmission enhancement polarizer 30 and absorb second polarized light from the liquid crystal Bragg brightness enhancement and transmission enhancement polarizer 30, so that the illumination light incident on the liquid crystal panel 21 is pure first polarized light, so that it can be better modulated into image light by the liquid crystal panel 21 and improve the display quality.

[0049] Optionally, such as Figure 2 and Figure 3As shown, the display panel 20 also includes a second polarizer 23 stacked on the liquid crystal panel 21 on the side opposite to the liquid crystal Bragg brightening and transmission enhancing polarizer 30. The second polarizer 23 is used to transmit the first polarized light from the liquid crystal panel 21 and absorb the second polarized light from the liquid crystal panel 21, so that the emitted image light is pure first polarized light, which is beneficial to improving the user's visual experience.

[0050] It is worth noting that the display panel 20 of this application can emit pure first polarized light through dual cleaning and filtering by the first polarizer 22 and the second polarizer 23, thereby achieving a higher quality display picture.

[0051] Furthermore, the first polarizer 22 and the second polarizer 23 mentioned in this application can both be implemented as conventional linear polarizers formed by stretching polymer materials; or, the first polarizer 22 and the second polarizer 23 can also be conventional liquid crystal polarizers made of cholesteric liquid crystal or smectic lamellar liquid crystal.

[0052] Preferably, such as Figure 2 and Figure 7 As shown, the first polarizer 22 is implemented as an interference-type liquid crystal polarizer 220, which may include an alignment substrate 221 and a plurality of liquid crystal dye layers 222. The plurality of liquid crystal dye layers 222 are sequentially stacked on one side of the alignment substrate 221, and each liquid crystal dye layer 222 is formed by mixing and coating a polymerizable nematic liquid crystal 2221 and a dichroic dye 2222. It is understood that the dichroic dye 2222 mentioned in this application may be a material containing iodine or a material containing dye, as long as it has dichroism, which will not be elaborated further in this application.

[0053] More preferably, such as Figure 7 As shown, along the direction away from the alignment substrate 221, the ratio of the convergent nematic liquid crystal 2221 and the dichroic dye 2222 in the liquid crystal dye layer 222 alternates between high and low. That is, the ratio of liquid crystal dye in any liquid crystal dye layer 222 is higher or lower than the ratio of liquid crystal dye in the two adjacent liquid crystal dye layers 222. This causes the effective refractive index of the liquid crystal dye layer 222 in the direction parallel to the long axis of the liquid crystal molecules to also alternate between high and low. In this way, for the second polarized light in the incident light, Bragg reflection will occur at the interface between the two adjacent liquid crystal dye layers 222, while for the first polarized light in the incident light, Bragg reflection will not occur due to refractive index matching.

[0054] It is worth noting that, since the convergent nematic liquid crystal 2221 controls the orientation of the dye molecules in the dichroic dye 2222 through the guest-host effect, that is, the dye molecules follow the orientation of the liquid crystal molecules, the second polarized light in the incident light will be both Bragg reflected and absorbed by the dichroic dye 2222 in the liquid crystal dye layer 222; while the first polarized light in the incident light will neither be Bragg reflected nor absorbed by the dichroic dye 2222. As a result, the second polarized light in the incident light cannot pass through the interferometric liquid crystal polarizer 220 due to reflection and absorption, while the first polarized light in the incident light can pass through the interferometric liquid crystal polarizer 220 smoothly, so as to achieve the light polarization filtering effect.

[0055] Furthermore, since both the interferometric liquid crystal polarizer 220 and the liquid crystal Bragg brightening and transmission enhancement polarizer 30 of this application are made of nematic liquid crystal material, the only difference is that the interferometric liquid crystal polarizer 220 requires mixing the nematic liquid crystal material with dichroic dyes, while the liquid crystal Bragg brightening and transmission enhancement polarizer 30 does not require the use of dichroic dyes. Therefore, the interferometric liquid crystal polarizer 220 and the liquid crystal Bragg brightening and transmission enhancement polarizer 30 of this application can be directly fused together due to their similar structures and identical processes to form a composite transmission enhancement polarizer, thereby eliminating the need for film composite processes and directly replacing the lower polarizer and DBEF film in existing liquid crystal display backlight modules.

[0056] Specifically, in one modified embodiment of this application, such as Figure 8 and Figure 9 As shown, the electronic device of this application may include a backlight 10, a display panel 20, and a liquid crystal Bragg brightening and transmission enhancing polarizer 30 disposed between the backlight 10 and the display panel 20. Specifically, as... Figure 9 As shown, the liquid crystal Bragg brightening and transmission enhancing polarizer 30 includes an alignment unit 31 and multiple Bragg structure units 32, and further includes multiple liquid crystal dye layers 222. The multiple liquid crystal dye layers 222 are stacked sequentially on the Bragg structure unit 32, and each liquid crystal dye layer 222 is formed by mixing and coating a polymerizable nematic liquid crystal 2221 and a dichroic dye 2222. This allows the multiple Bragg structure units 32 and the multiple liquid crystal dye layers 222 to share the same alignment unit 31 for the orientation control of liquid crystal molecules, so as to eliminate the alignment substrate 221 in the above-mentioned interference liquid crystal polarizer 220, which is beneficial to further thin the entire polarizer.

[0057] More specifically, such as Figure 8 As shown, the display panel 20 may include a liquid crystal panel 21 and a second polarizer stacked on the liquid crystal panel 21 on the side facing away from the backlight 10, so as to eliminate the need for the lower polarizer in a conventional liquid crystal display panel.

[0058] It is worth noting that, such as Figure 8 As shown, in this modified embodiment of the present application, the alignment unit 31 of the liquid crystal Bragg brightening and brightening polarizer 30 is arranged facing the backlight 10, such that a plurality of liquid crystal dye layers 222 are located between the plurality of Bragg structure units 32 of the liquid crystal Bragg brightening and brightening polarizer 30 and the liquid crystal panel 21 of the display panel 20.

[0059] Preferably, such as Figure 8 As shown, the outermost liquid crystal dye layer 222 of the liquid crystal Bragg brightening and transmission enhancing polarizer 30 is attached to the surface of the liquid crystal panel 21 facing the backlight 10.

[0060] Furthermore, along the direction away from the liquid crystal Bragg brightening and anti-reflection polarizer 30, the ratio of the polymerizable nematic liquid crystal 2221 and the dichroic dye 2222 in the liquid crystal dye layer 222 alternates between high and low values, serving to transmit first linearly polarized light and absorb second linearly polarized light. Thus, the composite anti-reflection polarizer of this application does not require the additional stacking of a quarter-wave plate as with cholesteric liquid crystal polarizers, nor does it require the co-extrusion and stretching process of hundreds or thousands of polymer materials as with DBEF films. Instead, it can be directly and simply coated, printed, and stacked, significantly reducing the manufacturing difficulty and cost.

[0061] It is worth mentioning that, according to another aspect of this application, such as Figure 10 As shown, one embodiment of this application further provides a method for preparing a liquid crystal Bragg brightening and transmission enhancing polarizer, which may include the following steps: S100: Dissolve different nematic liquid crystal monomers in a solvent to obtain at least two liquid crystal coating solutions; S200: Different liquid crystal coating liquids are alternately coated on one side of the alignment unit to form a plurality of Bragg structure units stacked sequentially on the alignment unit, such that each Bragg structure unit includes a first nematic liquid crystal layer and a second nematic liquid crystal layer with different unusual light refractive indices and thicknesses and stacked on each other.

[0062] It is worth noting that, such as Figure 10 As shown, the preparation method of the liquid crystal Bragg brightening and transmission enhancing polarizer of this application may further include the following steps: S300: Mix polymerizable nematic liquid crystal and dichroic dye according to a preset ratio to obtain at least two liquid crystal dye mixtures with different ratios; S400: Liquid crystal dye mixtures with different ratios are sequentially and alternately coated on the Bragg structure unit to form multiple liquid crystal dye layers that are sequentially stacked on the Bragg structure unit, such that the ratio between polymerizable nematic liquid crystal and dichroic dye in the liquid crystal dye layer alternates between high and low.

[0063] It is understood that the coating mentioned in this application may be implemented by, but is not limited to, spin coating, spray coating or roller coating, as long as the liquid crystal dye mixture can be coated into a film layer, and this application will not elaborate further.

[0064] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0065] The above embodiments are merely illustrative of several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application.

Claims

1. A liquid crystal Bragg polarizing film for brightening and enhancing light transmission, characterized in that, include: Alignment unit; and Multiple Bragg structure units are stacked sequentially on one side of the alignment unit; wherein each Bragg structure unit includes a first nematic liquid crystal layer and a second nematic liquid crystal layer stacked on top of each other, and the unusual light refractive index and thickness of the first nematic liquid crystal layer are different from the unusual light refractive index and thickness of the second nematic liquid crystal layer, respectively, for transmitting first linearly polarized light and reflecting second linearly polarized light perpendicular to the polarization direction of the first linearly polarized light.

2. The liquid crystal Bragg brightening and transmission-enhancing polarizer according to claim 1, characterized in that, Each of the Bragg structural units satisfies the following relation: n e1 ×d1=n e2 ×d2=λ / 4; where: n e1 d1 is the unusual optical refractive index of the first nematic liquid crystal layer, and n is the thickness of the first nematic liquid crystal layer; e2 d2 is the unusual light refractive index of the second nematic liquid crystal layer, d2 is the thickness of the second nematic liquid crystal layer, and λ is the reflection center wavelength of the Bragg structure unit.

3. The liquid crystal Bragg brightening and transmission-enhancing polarizer according to claim 1, characterized in that, The multiple Bragg structural units have different thicknesses.

4. The liquid crystal Bragg brightening and transmission-enhancing polarizer according to claim 3, characterized in that, Along the direction away from the alignment unit, the thickness of the Bragg structure unit increases or decreases sequentially.

5. The liquid crystal Bragg brightening and transmission-enhancing polarizer according to claim 1, characterized in that, The relative difference in unusual optical refractive index between the first nematic liquid crystal layer and the second nematic liquid crystal layer in each Bragg structural unit is greater than or equal to 20%.

6. The liquid crystal Bragg brightening and transmission-enhancing polarizer according to claim 5, characterized in that, The unusual light refractive index of the first nematic liquid crystal layer is 1.5; the unusual light refractive index of the second nematic liquid crystal layer is 2.

0.

7. The liquid crystal Bragg brightening and transmission enhancing polarizer according to any one of claims 1 to 6, characterized in that, The liquid crystal Bragg brightening and transmission enhancing polarizer also includes multiple liquid crystal dye layers; wherein the multiple liquid crystal dye layers are stacked sequentially on the Bragg structure unit, and each liquid crystal dye layer is formed by coating a mixture of polymerizable nematic liquid crystal and dichroic dye. Along the direction away from the liquid crystal Bragg brightening and brightening polarizer, the ratio of the polymerizable nematic liquid crystal and the dichroic dye in the liquid crystal dye layer alternates between high and low.

8. An electronic device, characterized in that, include: Backlight; Display panel; as well as The liquid crystal Bragg brightness enhancement and transmission enhancement polarizer as described in any one of claims 1 to 7 is disposed between the backlight and the display panel for transmitting first linearly polarized light from the backlight to the display panel and reflecting second linearly polarized light from the backlight back to the backlight.

9. The electronic device according to claim 8, characterized in that, The display panel includes a liquid crystal panel, a first polarizing element stacked on the liquid crystal panel facing the side of the liquid crystal Bragg brightening and brightening polarizer, and a second polarizing element stacked on the liquid crystal panel facing away from the liquid crystal Bragg brightening and brightening polarizer. The first polarizing element is a traditional linear polarizer, a conventional liquid crystal polarizer, or an interference-type liquid crystal polarizer.

10. The electronic device according to claim 8, characterized in that, The display panel includes a liquid crystal panel and a second polarizer stacked on the liquid crystal panel on the side facing away from the backlight; and the alignment unit of the liquid crystal Bragg brightening and transmission enhancing polarizer is arranged facing the backlight.

11. A method for preparing a liquid crystal Bragg brightening and transmission enhancing polarizer, characterized in that, Including the following steps: Different nematic liquid crystal monomers are dissolved in a solvent to obtain at least two liquid crystal coating solutions; and Different liquid crystal coating liquids are alternately coated on one side of the alignment unit to form a plurality of Bragg structure units stacked sequentially on the alignment unit, such that each Bragg structure unit includes a first nematic liquid crystal layer and a second nematic liquid crystal layer with different unusual refractive indices and thicknesses stacked on top of each other.

12. The method for preparing the liquid crystal Bragg brightening and transmission enhancing polarizer according to claim 11, characterized in that, It also includes the following steps: Mix polymerizable nematic liquid crystal and dichroic dye according to a preset ratio to obtain at least two liquid crystal dye mixtures with different ratios; and Different liquid crystal dye mixtures are alternately coated onto the Bragg structure unit to form multiple liquid crystal dye layers stacked sequentially on the Bragg structure unit, such that the ratio of polymerizable nematic liquid crystal and dichroic dye in the liquid crystal dye layer alternates between high and low.

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