WO2023273915A1

WO2023273915A1 - Brightness enhancement film and display apparatus

Info

Publication number: WO2023273915A1
Application number: PCT/CN2022/099350
Authority: WO
Inventors: 罗飞
Original assignee: 纳晶科技股份有限公司
Priority date: 2021-06-30
Filing date: 2022-06-17
Publication date: 2023-01-05
Also published as: CN113466978A; CN113466978B

Abstract

A brightness enhancement film (2B) and a display apparatus. The brightness enhancement film (2B) comprises a substrate and a microstructure layer located on the substrate; the microstructure layer comprises a plurality of first height prisms arranged at intervals and a plurality of second height prisms that are independently arranged; each first height prism and each second height prism both are arranged in a regular pattern; and the height of each second height prism is h2, the height of each first height prism is h1, and h1 is greater than h2. According to the display apparatus using the brightness enhancement film, the light emission can be more accurately controlled, light leakage is reduced, the blurring of the edge region of an displayed image is reduced, and the contrast of the display apparatus is improved.

Description

Brightness enhancement film and display device

technical field

The present disclosure relates to the field of backlight display, in particular, to a brightness enhancement film and a display device.

Background technique

Liquid crystal display is limited by pixel light leakage. Compared with new display technologies, contrast has become a short board. For this reason, liquid crystal display technology has gradually developed a partitioned backlight method, which controls the LED array of the backlight source in partitions. The backlight with different brightness can be controlled separately in each area, which can improve the above-mentioned pixel light leakage phenomenon to a certain extent and improve the display contrast. However, the display effect of the backlight partition control technology is positively correlated with the number of partitions. The more partitions, the more difficult the technology and the higher the cost. Limited by this, a more efficient solution is currently needed.

Contents of the invention

The purpose of the present disclosure is to provide a brightness enhancement film and a display device, which can efficiently reduce the pixel light leakage phenomenon of the liquid crystal display.

In order to achieve the above object, the following technical solution is adopted. According to the first aspect of the present disclosure, a brightness enhancement film is provided. The brightness enhancement film includes a substrate and a microstructure layer on the substrate, and the microstructure layer includes a plurality of The first height prism and a plurality of independently arranged second height prisms, each first height prism and each second height prism are arranged in a regular pattern, the height of each second height prism is h ₂ , each first height prism The height is h ₁ , and h ₁ is greater than h ₂ .

Further, h ₁ is less than 2h ₂ , preferably, h ₁ is less than 1.5h ₂ .

Further, the thickness of the substrate is h ₀ , the lateral width of the first height prism is d ₁ , the lateral width of the second height prism is d ₂ , and the lateral distance between two adjacent first height prisms is greater than or equal to

Further, d ₁ =d ₂ .

Further, the substrate includes one or more layers.

Further, the material of the microstructure layer is PMMA.

Further, the substrate includes quantum dots.

According to the second aspect of the present disclosure, there is provided a display device, the display device includes a plurality of zone-controlled backlight sources, a brightness enhancement film, and a display layer containing a plurality of pixel arrays, and the brightness enhancement film is any one of the above-mentioned Brightness Enhancement Film.

Further, the display device is a direct-type display device or an edge-type display device.

According to a third aspect of the present disclosure, a display device is provided, including a plurality of backlight light sources controlled by zones, and an optical device, which can perform secondary division on the light emitted by the backlight light sources controlled by zones, so that in the display device During operation, a plurality of secondary partitions are formed, and the density of the secondary partitions is higher than the density of the initial partitions of the backlight light source.

Applying the technical solution of the present disclosure, the prism structure can realize the emission of light nearly perpendicular to or perpendicular to the surface of the brightness enhancement film, and the height of the second height prism is higher than the height of the first height prism, so it can realize the reflection of the diffusion of part of the light Blocking to achieve further partitioning of the backlight, or secondary partitioning. Therefore, the light output is controlled more precisely, the light leakage is reduced, the blurring of the edge area of the displayed image is reduced, and the contrast ratio of the display device adopting the brightness enhancement film is improved.

Description of drawings

The accompanying drawings constituting a part of the present application are used to provide a further understanding of the present disclosure, and the exemplary embodiments and descriptions of the present disclosure are used to explain the present disclosure, and do not constitute undue limitations on the present disclosure. In the attached picture:

FIG. 1 shows a schematic diagram of a cross-sectional structure and a display effect of a direct-type display device in the prior art.

FIG. 2 shows a schematic diagram of a cross-sectional structure and a display effect of another direct-type display device in the prior art.

FIG. 3 shows a schematic diagram of a cross-sectional structure and a display effect of a direct-type display device according to an embodiment.

Fig. 4 shows a schematic diagram of the cross-sectional size structure of a brightness enhancing film according to an embodiment.

FIG. 5 shows a scale diagram of the partition size of the backlight light source in Embodiment 1. FIG.

FIG. 6 a shows a schematic diagram of the cross-sectional structure of the brightness enhancing film of Example 1. FIG.

FIG. 6 b shows a schematic cross-sectional structure diagram of a partially cut brightness enhancing film of Embodiment 1. FIG.

FIG. 6c shows a schematic side view of the three-dimensional structure of the brightness enhancing film of Example 1. FIG.

FIG. 6 d shows a schematic side view of a partially cut three-dimensional structure of the brightness enhancing film of Embodiment 1. FIG.

FIG. 7 shows the simulation results of the display screen of the display device of the first embodiment.

FIG. 8 shows the simulation results of the display screen of the display device of Comparative Example 1. Referring to FIG.

FIG. 9 shows the simulation results of the display screen of the display device of Comparative Example 2. Referring to FIG.

Reference signs: 1. Display layer; 2A, traditional brightness enhancement film; 2B, brightness enhancement film; 3A, non-partitioned backlight source; 3B, partitioned backlight source; Z1, light leakage area; Z2, set image display area.

Abbreviation description: BL is the backlight source. BL1 is the backlight light source of the first zone, BL2 is the backlight light source of the second zone, BL3 is the backlight light source of the third zone, and BL4 is the backlight light source of the fourth zone.

detailed description

It should be pointed out that the following detailed description is exemplary and intended to provide further explanation to the present application. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

It should be noted that the terms "first" and "second" in the specification and claims of the present disclosure are used to distinguish similar objects, and not necessarily used to describe a specific sequence or sequence. It should be understood that the data so used may be interchanged under appropriate circumstances for the embodiments of the disclosure described herein. Furthermore, the terms "comprising" and "having", as well as any variations thereof, are intended to cover a non-exclusive inclusion, for example, a process, method, system, product or device comprising a sequence of steps or elements is not necessarily limited to the expressly listed instead, may include other steps or elements not explicitly listed or inherent to the process, method, product or apparatus.

Exemplary implementations of the technical solution provided according to the present disclosure will be described in more detail below. These example embodiments may, however, be embodied in many different forms and should not be construed as limited to only the embodiments set forth herein. It should be understood that these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the concept of these exemplary embodiments to those of ordinary skill in the art.

In the prior art liquid crystal display device, the conventional optical plate or optical film is a whole piece of acrylic or other optical plastic materials. As shown in Figure 1, if the partition control of the backlight light source is not used, the light leakage will be serious, causing the pixels that do not need to be displayed to have light, such as the Z1 area, resulting in blurred image edges. As shown in Figure 2, if the backlight light source is used to control the switch and brightness of the backlight light source in partitions, since the optical transmission can be carried out inside the optical plate or optical film, except for the set image display area, the display layer directly above the BL1 and BL4 backlight light sources can receive The light from the BL2 and BL3 backlight sources irradiates above them (see the direction of the arrow, which refers to the direction of the light), and the Z1 area appears. Although the display effect is improved compared with that in Figure 1, there will still be light leakage from some pixels, resulting in the image to be displayed Edges are blurred, reducing contrast.

In order to solve the above problems, the first aspect of the present disclosure provides a brightness enhancement film, the brightness enhancement film includes a substrate and a microstructure layer on the substrate, the microstructure layer includes a plurality of first height prisms arranged at intervals and a plurality of independently arranged second height prisms, each first height prism and each second height prism are arranged in a regular pattern, the height of each second height prism is h ₂ , and the height of each first height prism is h ₁ , h ₁ is greater than h ₂ .

In order to illustrate the technical effect of the above-mentioned brightness enhancement film, Fig. 3 shows a schematic structural diagram of the display device and a schematic diagram of the display effect. Comparing the display effects of Fig. 3 and Fig. 2, it can be seen that the image display area set by Z2 should be white The area except the Z2 area is a non-display area. If Z1 is not pure black, it proves that there is light leakage, but the black of the Z1 light leakage area in Figure 3 is deeper than the black of the Z1 light leakage area in Figure 2, which means that the light is reduced. Bleed-out, which reduces the blurring of the edge areas of the displayed image. The prism structure (the first height prism and the second height prism) can realize that the light is nearly perpendicular to or perpendicular to the surface of the brightness enhancement film, and the height of the second height prism is higher than the height of the first height prism, so it can realize partial light emission. Diffuse reflective blocking to achieve further partitioning of the backlight, or secondary partitioning.

In some embodiments, the surface of the first height prism is provided with a reflective material, and the reflectivity of the reflective material is not less than 50%, preferably not less than 80%. The setting method may be coating. The reflective blocking effect of the reflective material is stronger than that of the first height prism, and the partitioning effect is more significant.

In some embodiments, the regular pattern arrangement includes but is not limited to, for example, the first height prisms are arranged in a row by b columns, the second height prisms are arranged in c rows by d columns, the number of each row and each column adjustable. The regular pattern arrangement can also be a combination of other regular repeating patterns. For example, the arrangement shown in FIG. 6 may of course also be a grid-like arrangement.

In some embodiments, the bottoms of any adjacent prisms (without distinguishing between the first height prism and the second height prism) are connected to each other, that is, the bottom interval between any two adjacent prisms is equal to zero.

The cross section of each prism is not limited, such as isosceles triangle, trapezoid, semicircle and so on. In some embodiments, each prism has a triangular cross-section. Each prism is a triangular pyramid. The top of the triangular pyramid can have a certain curvature, not sharp. In some embodiments, each prism has an approximately semicircular cross-section. In some embodiments, the first height prism and the second height prism can be made of different materials. In some embodiments, there may also be a third height prism, the third height prism is different from the second height prism, and the height of the third height prism is smaller than the first height prism. In some embodiments, more prisms of varying heights may also be included.

In some embodiments, h ₁ is less than 2h ₂ , preferably, h ₁ is less than 1.5h ₂ . Height affects the light blocking effect of the first height prism. In some embodiments, 3·˜5 second height prisms are arranged in a space between two adjacent first height prisms.

In some embodiments, the thickness of the substrate is h ₀ , the lateral width of the first height prism is d ₁ , the lateral width of the second height prism is d ₂ , and the lateral distance between two adjacent first height prisms is greater than or equal to

As shown in FIG. 4 , the critical condition for the light to be blocked is the line segment AB/AC=BD/CE, and thus the above calculation results are derived.

The height of the prism refers to the maximum value of the point on the cross-sectional figure perpendicular to the line segment of the substrate plane, and the lateral width of the prism refers to the maximum width of the contact surface between the prism and the substrate.

In some embodiments, for a prism with an isosceles triangular cross section, the base angle is arctan(h ₁ /d ₁ ).

In some embodiments, d ₁ =d ₂ . Thus, the preparation of the microstructure layer is facilitated.

In some embodiments, h2 ranges from ₂₅ to 55 microns. In some embodiments, there are other functional layers, such as an adhesive layer, between the microstructured layer and the substrate. In some embodiments, the material of the substrate is PET.

In some embodiments, a substrate includes one or more layers. There is no special requirement for the material of any layer of the base material, but it should be able to have a relatively high light extraction rate to meet the brightness requirement of the display device.

In some embodiments, the material of the microstructure layer is PMMA (polymethyl methacrylate), and reference can also be made to common brightness enhancing film materials. In other embodiments, the materials of the first height prism and the second height prism are different.

In some embodiments, quantum dots are included in the substrate. Quantum dots are included in one or more layers of the substrate to realize the function of light conversion. In some embodiments, diffusing particles are included in the substrate. Diffusion particles are contained in one or more layers of the substrate to realize light diffusion.

In some embodiments, the backlight light source is an LED, and the size of the LED is not particularly limited.

The second aspect of the present disclosure provides a display device, including a plurality of partition-controlled backlight sources, a brightness enhancement film, and a display layer containing a plurality of pixel arrays. membrane. A display device having the brightness enhancing film has a higher contrast ratio.

In some embodiments, the display device is a direct-type display device or an edge-type display device. How to realize partition control can refer to the prior art.

The third aspect of the present disclosure provides a display device, which includes a plurality of backlight sources controlled by zones, and also includes an optical device, which can perform secondary partitioning on the light emitted by the backlight sources controlled by zones, so that the display device During operation, a plurality of secondary partitions are formed, and the density of the secondary partitions is higher than the density of the initial partitions of the backlight light source. By further partitioning the backlight, smaller partitions are formed, thereby improving contrast.

In some embodiments, the above-mentioned optical device may be any one of the above-mentioned brightness enhancement films. In some embodiments, the above-mentioned optical device is a diffusion plate or a diffusion film or a light guide plate.

The present application will be described in further detail below in conjunction with specific examples, and these examples should not be construed as limiting the scope of protection claimed in the present application.

Example 1

direct display device

After optical software simulation: the selected display area is 80mm×50mm. The set display image is a hollow figure as shown in FIG. 7 , and the set display transmittance (or light leakage rate) is 10%.

As shown in Figure 5, the 80mm×50mm backlight light source is divided into 16 rectangular backlight partitions of 19.99mm×12.49mm. For the convenience of software simulation, the backlight partition interval is set to 0.02mm (the setting on the software is the line width of the dividing line) ), and the backlight source is set to a uniform light-emitting field type.

As shown in Figures 6a, 6b, 6c, and 6d, a brightness-enhancing film of 80mm×50mm is set, the PET substrate, the prism material is PMMA, and the thickness of the substrate is 125μm; the height of the second height prism is 25μm, and the cross section is the top angle It is a right-angled right triangle with a lateral width of 50 μm; the height of the first height prism is 62.5 μm, the cross section is triangular, and the lateral width is 50 μm; the second height prism and the first height prism are arranged in a horizontal and vertical array, and every two Four second height prisms are arranged between the first height prisms. The pre-set display patterns are geometric figures and English letters. The simulation results are shown in FIG. 7, and the horizontal and vertical coordinate units are dimensions (mm), the same below.

Comparative example 1

direct display device

The difference from Example 1 is that there is no partition of the backlight light source and no special brightness enhancement film, and a conventional brightness enhancement film is used. A brightness enhancing film having the same size and material as in Example 1, the thickness of the substrate is 125 μm, the height of the prisms is 25 μm, the cross section is a right-angled triangle with a right angle at the apex, and the lateral width is 50 μm, and the prisms are evenly arranged. The preset display patterns are as in Example 1, and the simulation results are shown in FIG. 8 .

Comparative example 2

direct display device

The difference from Example 1 is that there is no special brightness enhancing film. The brightness enhancing film used was the same as in Comparative Example 1. The preset display patterns are as in Example 1, and the simulation results are shown in FIG. 9 .

It should be noted that due to the limitation of software and display resolution, the applicant increased the brightness of the simulation results by 10% at the same time to obtain Figures 7 to 9, so as to facilitate the viewing of the differences in simulation results. In combination with FIGS. 7 to 9 , the display device in FIG. 7 has the best display effect, and gray scales other than text hardly exist. In Figure 9, there is a certain gray level; in Figure 8, there is a larger range of gray levels. Therefore, the technical solution of Embodiment 1 can reduce light leakage and have the effect of improving contrast.

The above descriptions are only preferred embodiments of the present disclosure, and are not intended to limit the present disclosure. For those skilled in the art, the present disclosure may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present disclosure shall be included within the protection scope of the present disclosure.

Claims

A brightness enhancement film, characterized in that the brightness enhancement film comprises a base material and a microstructure layer located on the base material, and the microstructure layer comprises a plurality of first height prisms arranged at intervals and a plurality of independently arranged The second height prisms, each of the first height prisms and each of the second height prisms are arranged in a regular pattern, the height of each of the second height prisms is h 2 , and the height of each of the first height prisms The height is h 1 , and h 1 is larger than h 2 .
The brightness enhancing film according to claim 1, characterized in that h 1 is less than 2h 2 , preferably, h 1 is less than 1.5h 2 .
The brightness enhancing film according to claim 1, wherein the thickness of the substrate is h 0 , the lateral width of the first height prism is d 1 , and the lateral width of the second height prism is d 2 , the lateral distance between two adjacent first height prisms is greater than or equal to
The brightness enhancing film according to claim 3, characterized in that d 1 =d 2 .
The brightness enhancing film according to claim 1, wherein the substrate comprises one or more layers.
The brightness enhancing film according to claim 1, characterized in that the material of the microstructure layer is PMMA.
The brightness enhancing film according to claim 1, wherein the substrate includes quantum dots.
A display device, characterized in that it includes a plurality of backlight sources controlled by zones, a brightness enhancement film, and a display layer containing a plurality of pixel arrays, and the brightness enhancement film is any one of claims 1-7. Brightness Enhancement Film.
The display device according to claim 8, wherein the display device is a direct-type display device or an edge-type display device.
A display device, which is characterized in that it includes a plurality of backlight sources controlled by zones, and also includes an optical device, which can perform secondary partitioning on the light emitted by the backlight sources controlled by zones, so that in the display device During operation, a plurality of backlights of secondary divisions are formed, and the density of the secondary divisions is higher than that of the initial divisions of the light source of the backlight.