Direct backlight module and display panel
By employing a multi-layer diffusion structure design in the direct-lit backlight module, the problem of uneven brightness caused by the compression of the light mixing distance is solved, thereby improving the brightness uniformity and display effect of the display panel.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- DONGGUAN DEHONG DISPLAY TECHNOLOGY CO LTD
- Filing Date
- 2025-09-03
- Publication Date
- 2026-06-09
AI Technical Summary
In direct-lit backlight design, excessive compression of the light mixing distance makes it difficult to shield the bright and dark boundaries between the LEDs, reducing the area of light superposition and affecting the display effect of the display device.
The design employs a multi-layer diffusion structure, including a first diffusion structure and a second diffusion structure located on the first surface of the diffusion plate. By setting a smaller area for the first diffusion structure, the brightness directly above the light source is suppressed, while the larger area for the second diffusion structure supplements the dark area, thereby improving brightness uniformity.
It effectively reduces the brightness difference between the central bright spot and the dark area, improving the brightness uniformity and display effect of the display panel.
Smart Images
Figure CN224341757U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of liquid crystal display technology, and in particular to a direct-lit backlight module and display panel. Background Technology
[0002] In direct-lit backlight designs, the mixing distance between the LED chips and the light-diffusing components (such as diffusers) has a decisive impact on display performance. The greater the mixing distance, the more fully the light diffuses during transmission, which can effectively reduce the graininess of the LED chips and improve the light-diffusing effect of the diffuser.
[0003] In related technologies, to achieve thinner and lighter display devices, structural thinning is usually achieved by significantly reducing the light mixing distance. However, excessive compression of the light mixing distance can cause significant problems: the boundaries between light and dark LEDs are difficult to shield, the area of light superposition is reduced, and the display effect of the display device is affected. Utility Model Content
[0004] Therefore, it is necessary to provide a direct-lit backlight module and display panel that can improve the display effect of display devices, addressing the aforementioned technical problems.
[0005] In a first aspect, this application provides a direct-lit backlight module, comprising:
[0006] substrate;
[0007] A light source is located on one side of the substrate;
[0008] A diffusion module, located on the side of the light source away from the substrate, includes a diffusion plate, a first diffusion structure, and a second diffusion structure; the diffusion plate includes a first surface and a second surface disposed opposite to each other; the first surface is closer to the light source than the second surface; the first diffusion structure is located on the first surface; and the second diffusion structure is located on the second surface.
[0009] Wherein, the first projection of the light source on the target plane falls into the second projection of the first diffusion structure on the target plane; the second projection falls into the third projection of the second diffusion structure on the target plane; the area of the first projection is smaller than the area of the second projection, and the area of the second projection is smaller than the area of the third projection; the target plane is the plane where the substrate is located.
[0010] In one embodiment, the number of the light source, the first diffusion structure, and the second diffusion structure is multiple;
[0011] At least one of the light sources has a first projection onto the target plane that falls into a second projection onto the target plane of the first diffusion structure; at least one of the second projections falls into a third projection onto the target plane of the second diffusion structure.
[0012] In one embodiment, the center of the first projection of the light source, the center of the second projection of the corresponding first diffusion structure, and the center of the third projection of the corresponding second diffusion structure are located on the same virtual straight line in a first direction, where the first direction is the direction from the first diffusion structure to the second diffusion structure.
[0013] In one embodiment, the direct-lit backlight module further includes:
[0014] An encapsulating adhesive structure is located between the light source and the diffuser plate, and covers the light source;
[0015] The refractive index of the encapsulating adhesive structure is positively correlated with the light emission angle of the light source.
[0016] In one embodiment, the area of the second projection and the area of the third projection are both positively correlated with the light emission angle of the light source.
[0017] In one embodiment, the reflectivity of the second diffusion structure is greater than that of the first diffusion structure.
[0018] In one embodiment, the thickness of the second diffusion structure in the first direction is greater than or equal to the thickness of the first diffusion structure in the first direction; the first direction is the direction in which the first diffusion structure points to the second diffusion structure.
[0019] In one embodiment, the second projection and the third projection have similar shapes.
[0020] In one embodiment, the distance between the light source and the first surface of the diffuser plate in a first direction is less than or equal to 1 mm, where the first direction is the direction from the first diffuser structure to the second diffuser structure.
[0021] Secondly, this application provides a display panel, including an optical film and the direct-lit backlight module described in any of the above embodiments.
[0022] The aforementioned direct-lit backlight module and display panel include a substrate, a light source, a diffuser plate, a first diffuser structure located on a first surface of the diffuser plate, and a second diffuser structure located on a second surface of the diffuser plate. The first projection of the light source onto the target plane falls into the second projection of the first diffuser structure onto the target plane, with the area of the first projection being smaller than the area of the second projection. Simultaneously, the second projection falls into the third projection of the second diffuser structure onto the target plane, with the area of the second projection being smaller than the area of the third projection. By using a smaller-area first diffuser structure, the direct, intense light emitted by the light source can be diffused to the surrounding area, preventing excessive brightness directly above the light source and reducing the brightness difference between the central bright spot and the dark area. Furthermore, by using a larger-area second diffuser structure, further illumination can be provided to the dark area, thereby improving the brightness uniformity of the display panel. Attached Figure Description
[0023] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0024] Figure 1 This is a cross-sectional schematic diagram of a direct-lit backlight module in one embodiment;
[0025] Figure 2 This is a cross-sectional schematic diagram of a direct-lit backlight module in another embodiment;
[0026] Figure 3 This is a cross-sectional schematic diagram of a direct-lit backlight module in another embodiment;
[0027] Figure 4 This is a schematic diagram of the second projection of the first diffusion structure in one embodiment;
[0028] Figure 5 This is a schematic diagram of the third projection of the second diffusion structure in one embodiment;
[0029] Figure 6 This is a cross-sectional schematic diagram of a direct-lit backlight module in yet another embodiment;
[0030] Figure 7 This is a cross-sectional schematic diagram of a direct-lit backlight module in another embodiment.
[0031] Explanation of reference numerals in the attached drawings: 10-substrate, 21-light source, 31-first diffusion structure, 311-second projection, 32-second diffusion structure, 321-third projection, 33-diffusion plate, 41-encapsulation adhesive structure. Detailed Implementation
[0032] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of this application.
[0033] Unless otherwise defined, 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. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.
[0034] When describing positional relationships, unless otherwise specified, when an element, such as a layer, film, or substrate, is referred to as being "on" another element, it may be directly on the other element or there may be intermediate elements present. Furthermore, when a layer is referred to as being "below" another layer, it may be directly below it or there may be one or more intermediate elements present. It is also understood that when a layer is referred to as being "between" two layers, it may be the only layer between the two layers, or there may be one or more intermediate elements present.
[0035] When using the terms “including,” “having,” and “comprising” as described herein, another component may be added unless explicitly qualifying terms such as “only,” “consisting of,” etc. are used. Unless otherwise stated, singular terms may include plural forms and should not be construed as having a quantity of one.
[0036] It should be understood that although the terms “first,” “second,” etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, without departing from the scope of this application, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element.
[0037] It should also be understood that, in interpreting an element, although not explicitly described, the element is interpreted as including a range of error, which should be within the acceptable deviation range of a particular value as determined by a person skilled in the art. For example, "approximately," "about," or "substantially" can mean within one or more standard deviations, without limitation herein.
[0038] Furthermore, in the instruction manual, the phrase "planar distribution diagram" refers to the diagram when the target part is viewed from above, and the phrase "cross-sectional diagram" refers to the diagram when the target part is viewed from the side as a cross-section taken by vertically cutting the target part.
[0039] Furthermore, the accompanying drawings are not drawn to a 1:1 scale, and the relative dimensions of the components are shown in the drawings only as examples and not necessarily to actual scale.
[0040] As described in the background section, with the rise of flat-panel TVs, flat-panel TVs have largely replaced CRT (Cathode Ray Tube) displays. Among them, LCD TVs are a type of flat-panel TV.
[0041] LCD TVs, because their LCD panels cannot emit light themselves, require a backlight module to provide the light source for image display. Depending on the installation location of the light source, existing backlight modules are divided into two types: direct-lit and edge-lit.
[0042] A direct-lit backlight module typically includes an optical film, a diffuser plate, and a light source. The optical film is positioned above the diffuser plate, which in turn is positioned above the light source, separated by a mixing distance. The mixing distance between the light source and the diffuser plate has a decisive impact on display performance; a larger mixing distance results in more complete light diffusion during transmission, leading to more uniform brightness of the backlight when viewed from above the optical film. Typically, a mixing distance of 5-8mm is required for sufficient light diffusion. However, this results in a thicker direct-lit backlight module, hindering the design of thinner LCD TVs. Reducing the mixing distance can decrease the thickness of the direct-lit backlight module, but this leads to uneven brightness. A smaller mixing distance results in brighter light emitted from the area above the light source (high center brightness), while the light emitted from the areas between the light sources is dimmer (low brightness in dark areas), causing uneven brightness. The light emitted above each light source is relatively dim, mainly because less light reaches the area above the light sources. This less light is further absorbed by the optical film, causing the light emitted from that position to decrease again, resulting in a dim light emission at that position.
[0043] To address the aforementioned technical problems, please refer to some exemplary embodiments. Figure 1 This application provides a direct-lit backlight module, comprising:
[0044] Substrate 10.
[0045] The light source 21 is located on one side of the substrate 10.
[0046] The diffusion module 30 is located on the side of the light source 21 away from the substrate 10, and includes a first diffusion structure 31, a second diffusion structure 32 and a diffusion plate 33. The diffusion plate 33 includes a first surface and a second surface disposed opposite to each other. The first surface is closer to the light source 21 than the second surface. The first diffusion structure 31 is located on the first surface. The second diffusion structure 32 is located on the second surface.
[0047] The first projection of the light source 21 onto the target plane falls into the second projection of the first diffusion structure 31 onto the target plane; the second projection falls into the third projection of the second diffusion structure 32 onto the target plane; the area of the first projection is smaller than the area of the second projection, and the area of the second projection is smaller than the area of the third projection; the target plane is the plane where the substrate 10 is located.
[0048] It is understood that the area directly above the light source 21 is the region with the strongest direct light, i.e., the brightness peak area. In this application, due to the provision of the first diffusion structure 31, the area of the second projection of the first diffusion structure 31 on the target plane is larger than the area of the first projection of the light source 21 on the target plane. Therefore, after the light directly from the light source 21 enters the first diffusion structure, the first diffusion structure 31 can disperse the light directly from the light source 21 to the surrounding area, avoiding excessive brightness directly above the light source 21 and reducing the brightness difference between the area directly above the light source 21 and the surrounding area from the source. After the light is diffused by the first diffusion structure 31 on the first surface of the diffusion plate 33, the gap area between each light source 21 (i.e., the dark area) may still have insufficient brightness. Therefore, in this application, a second diffusion structure is provided on the second surface of the diffusion plate 33 to further reflect the light directly from the light source 21, guide more light to the dark area, suppress stray light, and improve the brightness of the dark area.
[0049] The aforementioned direct-lit backlight module includes a substrate, a light source, a diffuser plate, a first diffuser structure located on a first surface of the diffuser plate, and a second diffuser structure located on a second surface of the diffuser plate. The first projection of the light source onto the target plane falls into the second projection of the first diffuser structure onto the target plane, with the area of the first projection being smaller than the area of the second projection. Simultaneously, the second projection falls into the third projection of the second diffuser structure onto the target plane, with the area of the second projection being smaller than the area of the third projection. By using a smaller-area first diffuser structure, the direct, intense light emitted by the light source can be diffused to the surrounding area, preventing excessive brightness directly above the light source and reducing the brightness difference between the central bright spot and the dark area. Furthermore, by using a larger-area second diffuser structure, further illumination can be provided to the dark areas, thereby improving the brightness uniformity of the display panel.
[0050] In some exemplary embodiments, the reflectivity of the second diffusion structure 32 is greater than that of the first diffusion structure 31.
[0051] In this embodiment, the core function of the first diffusion structure 31 is to suppress the brightness directly above the light source 21, rather than to completely reflect the light. The function of the first diffusion structure 31 needs to balance between "dispersing strong light" and "retaining enough light for subsequent propagation". If the reflectivity of the first diffusion structure 31 is too high (such as greater than or equal to the reflectivity of the second diffusion structure 32), it will excessively reflect the light emitted by the light source, resulting in a reduction in the total amount of light entering the diffusion plate 33, which in turn causes a decrease in overall brightness.
[0052] The core function of the second diffusion structure 32 is to efficiently fill the brightness of the dark area. After being diffused by the first diffusion structure 31, the light reaching the second diffusion structure 32 is dispersed and its intensity is reduced. It is necessary to capture these dispersed weak lights efficiently through higher reflectivity and reflect them to the dark area between the lamp beads. If the reflectivity of the second diffusion structure 32 is too low, the efficiency of capturing and reflecting weak light will be insufficient, and it will be unable to effectively improve the brightness of the dark area. The filling effect will be greatly weakened, and it will be difficult to achieve overall brightness uniformity.
[0053] Therefore, in this application, the reflectivity of the second diffusion structure 32 is set to be greater than that of the first diffusion structure 31. For example, the reflectivity of the second diffusion structure 32 is 80%, and the reflectivity of the first diffusion structure 31 is 70%. Since the first diffusion structure 31 faces the direct light from the light source 21, even with a slightly lower reflectivity, it can still suppress the brightness directly above the light source 21 by reflecting enough strong light, and the remaining light can continue to propagate upwards. The second diffusion structure 32 faces the light whose intensity has decreased after diffusion, requiring a higher reflectivity to ensure that the light reflected to the dark area still has sufficient intensity, effectively reducing the brightness difference between the dark and bright areas, and avoiding the "ineffective" supplementary lighting due to insufficient light.
[0054] In some exemplary embodiments, there are multiple light sources 21, first diffusion structures 31, and second diffusion structures 32.
[0055] At least one light source 21 has a first projection onto the target plane, which falls into a second projection onto the target plane of a first diffusion structure 31; at least one second projection falls into a third projection onto the target plane of a second diffusion structure 32.
[0056] In one example, a first diffusion structure 31 can be configured to correspond to at least one light source 21, and a second diffusion structure 32 can correspond to at least one first diffusion structure 31. For example, please refer to... Figure 2 The first projection of the two light sources 21 onto the target plane falls into the second projection of the first diffusion structure 31 onto the target plane, and the second projection of the first diffusion structure 31 onto the target plane falls into the third projection of the second diffusion structure 32 onto the target plane. That is, one first diffusion structure 31 corresponds to two light sources 21, and one second diffusion structure 32 corresponds to one first diffusion structure 31.
[0057] In another example, the center of the first projection of the light source 21, the center of the second projection of the corresponding first diffusion structure 31, and the center of the third projection of the corresponding second diffusion structure 32 are located on the same virtual straight line in a first direction, which is the direction from the first diffusion structure 31 to the second diffusion structure 32.
[0058] Please see Figure 3 There are multiple light sources 21, first diffusion structures 31, and second diffusion structures 32, and the straight lines extending along the first direction intersect the target plane. The light sources 21, first diffusion structures 31, and second diffusion structures 32 are arranged in a one-to-one correspondence, with the first direction being... Figure 3 As shown in the X-axis direction, and taking one of the corresponding light sources 21, the first diffusion structure 31 and the second diffusion structure 32 as an example, it can be seen that the centers of the light source 21, the first diffusion structure 31 and the second diffusion structure 32 are located on the virtual straight line L extending along the first direction.
[0059] In this embodiment, by setting the light source 21 and the corresponding first diffusion structure 31 to be collinear in the first direction, the direct intense light emitted by the light source 21 can be perpendicularly incident on the central region of the corresponding first diffusion structure 31. This ensures that the direct intense light emitted by the light source 21 is reflected by the first diffusion structure 31, and avoids the situation where part of the direct intense light is excessively suppressed due to the offset of the center of the first diffusion structure 31 relative to the center of the corresponding light source 21, resulting in localized darkness, while another part is not sufficiently suppressed, resulting in residual bright spots. This avoids uneven brightness. At the same time, by setting the projection centers of the first diffusion structure 31 and the corresponding second diffusion structure 32 to be collinear in the first direction, the central axis of the propagation direction of the scattered light processed by the first diffusion structure 31 can be aligned with the center of the second diffusion structure 32, improving the light reflection efficiency of the second diffusion structure 32.
[0060] In some exemplary embodiments, the light sources 21 on the substrate 10 can be arranged in an array. Correspondingly, the first diffusion structures 31 on the first surface of the diffusion plate 33 are also arranged in an array, and the second diffusion structures 32 on the second surface of the diffusion plate 33 are also arranged in an array. The shapes of the first diffusion structures 31 and the second diffusion structures 32 can be similar, and correspondingly, the shapes of the second projection of the first diffusion structure 31 and the third projection of the second diffusion structure 32 are also similar. For example, the second projection of the first diffusion structure 31 and the third projection of the second diffusion structure 32 can be triangular, circular, polygonal, or other shapes.
[0061] In this embodiment, by setting the second and third projections to have similar shapes, it can be ensured that the diffusion of light between the first diffusion structure 31 and the second diffusion structure 32 is consistent and regular. This helps to control the propagation and distribution of light more accurately, avoid abnormal light distribution caused by differences in the shape of the diffusion structures, thereby improving the stability and reliability of the backlight module and making the quality of the display image more stable.
[0062] In one example, see Figure 4 and Figure 5 , Figure 4 This is a schematic diagram of the second projection 311 of each of the first diffusion structures 31 on the target plane of the first surface of the diffusion plate 33 in an example. Figure 5 This is a schematic diagram of the third projection 321 of each of the second diffusion structures 32 on the target plane of the second surface of the diffuser plate 33 in an example, where the Y-axis direction is the second direction and the Z-axis direction is the third direction. In this example, it is assumed that the centers of any two adjacent light sources 21 are 5mm apart in the second direction, and the centers of any two adjacent light sources 21 are also 5mm apart in the third direction, such as... Figure 4 As shown, the centers of any two adjacent first diffusion structures 31 are also 5 mm apart in the second direction, and the centers of any two adjacent first diffusion structures 31 are also 5 mm apart in the third direction, as shown. Figure 5 As shown, the centers of any two adjacent second diffusion structures 32 are also 5 mm apart in the second direction, and the centers of any two adjacent second diffusion structures 32 are also 5 mm apart in the third direction.
[0063] In this embodiment, by setting the projection centers of the light source 21, the corresponding first diffusion structure 31, and the corresponding second diffusion structure 32 to lie on the same virtual straight line, the relative regularity of the light propagation path is ensured. Light can pass through each diffusion structure more concentratedly and sequentially, reducing light scattering loss and improving light utilization efficiency. This enhances the uniform light effect of the backlight module while maintaining brightness, resulting in a clearer and softer display image.
[0064] In some exemplary embodiments, please refer to Figure 6 The direct-lit backlight module also includes an encapsulating adhesive structure 41, located between the light source 21 and the diffuser plate 33, and covering the light source 21. The refractive index of the encapsulating adhesive structure 41 is positively correlated with the light emission angle of the light source 21, and the areas of the second and third projections are both positively correlated with the light emission angle of the light source.
[0065] It is understood that there can be multiple encapsulation structures 41, and each light source 21 corresponds to one encapsulation structure 41. It is understood that the greater the refractive index of the encapsulation structure 41, the greater the light emission angle of the light source 21. Consequently, the first diffusion structure 31 and the second diffusion structure 32 need to be set larger on the diffusion plate, that is, the area of the second projection of the first diffusion structure 31 and the area of the third projection of the second diffusion structure 32 are larger.
[0066] In this embodiment, by setting the encapsulating adhesive structure 41, the light source 21 can be protected. Furthermore, by setting the area of the second projection and the area of the third projection to be positively correlated with the light emission angle of the light source, the light diffusion range can be adaptively adjusted according to the different light emission angles of the light source, ensuring that light sources with different light emission angles can achieve good diffusion effects, improving the uniformity and coverage of the light, and making the backlight module more applicable.
[0067] In some exemplary embodiments, when preparing the first diffusion structure 31 and the second diffusion structure 32, a layer of white ink dots can be screen-printed on the first and second surfaces of the diffusion plate 33 using a mask, wherein the ink refractive index can be between 1.6 and 1.8. In application, the thickness of the second diffusion structure 32 in the first direction can be between 10 and 15 μm, and the thickness of the first diffusion structure 31 in the first direction can be between 7 and 10 μm.
[0068] The type of ink used in preparing the first diffusion structure 31 may be the same as the type of ink used in preparing the second diffusion structure 32; or the type of ink used in preparing the first diffusion structure 31 may be different from the type of ink used in preparing the second diffusion structure 32.
[0069] In one example, when the first diffusion structure 31 and the second diffusion structure 32 are prepared using the same type of ink, the reflectivity of the white ink dots is positively correlated with the thickness of the white ink dots. In order to ensure that the reflectivity of the second diffusion structure 32 is greater than that of the first diffusion structure 31, the thickness of the second diffusion structure 32 in the first direction can be controlled to be greater than that of the first diffusion structure 31 in the first direction.
[0070] In another example, when different types of ink are used to prepare the first diffusion structure 31 and the second diffusion structure 32, the second diffusion structure 32 can be prepared using ink with higher reflectivity and the first diffusion structure 31 can be prepared using ink with lower reflectivity. Since the reflectivity of the ink used to prepare the second diffusion structure 32 is greater than that of the ink used to prepare the first diffusion structure 31, the thickness of the second diffusion structure 32 in the first direction can be controlled to be equal to the thickness of the first diffusion structure 31 in the first direction.
[0071] In some exemplary embodiments, please refer to Figure 7 The distance D between the light source 21 and the first surface of the diffuser plate 33 in the first direction is less than or equal to 1 mm.
[0072] In a detailed embodiment, before fabricating the first diffusion structure 31 and the second diffusion structure 32, optical simulation is first performed. Taking the light emission angle of the light source 21 as 140°, the center spacing of any two adjacent light sources 21 in the second direction and the third direction as 5 mm, and the distance D between the light source 21 and the first surface of the diffusion plate 33 in the first direction as 0.4 mm, the bright spot size boundary (center brightness 90%) is calculated through angular distribution and spatial superposition effect. Based on the bright spot size and the screen printing process accuracy limit (±0.5 mm), the initial parameters of the white high-reflectivity ink dots on the first surface are determined. Taking the bright spot radius as the side length of the square ink, the diameter of the first diffusion structure 31 is determined to be 1 mm and the spacing is 5 mm to ensure the lateral diffusion coverage of narrow-angle light. Subsequently, the dot model of the first surface is imported into the optical path, and the energy distribution of the light field is recalculated. For the stray light characteristics of the light source 21, the optimization algorithm is called to iteratively solve the size of the white ink dots on the second surface, and the diameter of the second diffusion structure 32 is determined to be 3 mm and the center spacing is 5 mm, so as to maximize the brightness uniformity while suppressing glare.
[0073] Furthermore, a direct-lit backlight module can be fabricated. First, a substrate 10 is provided, with a high-reflectivity reflective paper (96% reflectivity) screen-printed on the upper surface of the substrate 10, and multiple light sources 21 arranged in an array. The light sources 21 are covered with an encapsulating adhesive structure 41. The center-to-center spacing of the light sources 21 is 5 mm, and the light emission angle is 140°. The diffuser plate 33 is made of a 0.7 mm thick glass substrate. A layer of white ink dots (70% reflectivity, 7-10 μm thickness) is screen-printed on the first surface of the diffuser plate 33 to form a square dot matrix with a diameter of 1 mm and a center-to-center spacing of 5 mm, thereby fabricating multiple first diffuser structures 31. Forced lateral diffusion compensates for insufficient light spot overlap under small mixing distances, reducing the brightness difference between the central bright spot and the dark area. Next, a layer of white ink dots (80% reflectivity, 10-15 μm thickness) is screen-printed on the second surface of the diffuser plate 33 to form a square dot matrix with a diameter of 3 mm and a center-to-center spacing of 5 mm, thereby fabricating multiple second diffuser structures 32 for brightness compensation in the dark area, suppressing stray light, and optimizing overall uniformity.
[0074] In some exemplary embodiments, this application provides a display panel including an optical film and a direct-lit backlight module as described in any of the above embodiments. The optical film is located on the side of the diffusion module away from the substrate.
[0075] In the description of this specification, references to terms such as "some embodiments," "other embodiments," and "ideal embodiments" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative descriptions of the above terms do not necessarily refer to the same embodiments or examples.
[0076] 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.
[0077] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model 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. Therefore, the protection scope of this patent application should be determined by the appended claims.
Claims
1. A direct-lit backlight module, characterized in that, include: substrate; A light source is located on one side of the substrate; A diffusion module, located on the side of the light source away from the substrate, includes a diffusion plate, a first diffusion structure, and a second diffusion structure; the diffusion plate includes a first surface and a second surface disposed opposite to each other; the first surface is closer to the light source than the second surface. The first diffusion structure is located on the first surface; The second diffusion structure is located on the second surface; Wherein, the first projection of the light source on the target plane falls into the second projection of the first diffusion structure on the target plane; the second projection falls into the third projection of the second diffusion structure on the target plane; the area of the first projection is smaller than the area of the second projection, and the area of the second projection is smaller than the area of the third projection; the target plane is the plane where the substrate is located.
2. The direct-lit backlight module according to claim 1, characterized in that, The number of the light source, the first diffusion structure, and the second diffusion structure is multiple; At least one of the light sources has a first projection onto the target plane that falls into a second projection onto the target plane of the first diffusion structure; at least one of the second projections falls into a third projection onto the target plane of the second diffusion structure.
3. The direct-lit backlight module according to claim 1, characterized in that, The center of the first projection of the light source, the center of the second projection of the corresponding first diffusion structure, and the center of the third projection of the corresponding second diffusion structure are located on the same virtual straight line in a first direction, which is the direction from the first diffusion structure to the second diffusion structure.
4. The direct-lit backlight module according to claim 1, characterized in that, The direct-lit backlight module also includes: An encapsulating adhesive structure is located between the light source and the diffuser plate, and covers the light source; The refractive index of the encapsulating adhesive structure is positively correlated with the light emission angle of the light source.
5. The direct-lit backlight module according to claim 1, characterized in that, The area of the second projection and the area of the third projection are both positively correlated with the light emission angle of the light source.
6. The direct-lit backlight module according to claim 1, characterized in that, The reflectivity of the second diffusion structure is greater than that of the first diffusion structure.
7. The direct-lit backlight module according to claim 1, characterized in that, The thickness of the second diffusion structure in the first direction is greater than or equal to the thickness of the first diffusion structure in the first direction; the first direction is the direction in which the first diffusion structure points to the second diffusion structure.
8. The direct-lit backlight module according to claim 1, characterized in that, The second projection and the third projection have similar shapes.
9. The direct-lit backlight module according to claim 1, characterized in that, The distance between the light source and the first surface of the diffuser plate in a first direction is less than or equal to 1 mm, where the first direction is the direction from the first diffuser structure to the second diffuser structure.
10. A display panel, characterized in that, Includes optical films and the direct-lit backlight module as described in any one of claims 1-9.