Light guide plate, backlight module and display device

Abstract

The disclosure provides a light guide plate, comprising: a light guide plate body having a light emitting surface, a plurality of first annular regions are divided on the light emitting surface, and the centers of all the first annular regions coincide with the center of the light emitting surface; a corresponding light converging structure is arranged in each first annular region, the orthographic projection of the light converging structure on the light emitting surface exactly covers the corresponding first annular region, and the light converging structure is used for limiting the light emitting angle of the corresponding first annular region. The disclosure also provides a backlight module and a display device.

Description

Technical Field

[0001] This disclosure relates to the field of display technology, and in particular to a light guide plate, a backlight module, and a display device. Background Technology

[0002] To achieve privacy protection, existing side-lit privacy backlight modules typically add a privacy film between the diaphragm and the liquid crystal glass. This privacy film has a louver structure, and by controlling the angle of the louvers in the privacy film, the angle of light emission is changed to achieve the privacy protection function. Summary of the Invention

[0003] This disclosure aims to solve at least one of the technical problems existing in the prior art, and proposes a light guide plate, a backlight module, and a display device.

[0004] In a first aspect, the present disclosure provides a light guide plate, including: a light guide plate body, the light guide plate body having a light emitting surface, the light emitting surface being divided into a plurality of nested first annular regions, the center of all the first annular regions coinciding with the center of the light emitting surface;

[0005] Each of the first annular regions is provided with a corresponding light convergence structure. The orthographic projection of the light convergence structure on the light-emitting surface exactly covers the corresponding first annular region. The light convergence structure is used to limit the light emission angle of the corresponding first annular region.

[0006] In some embodiments, all of the first annular regions are circular annular regions;

[0007] Alternatively, all of the first annular regions may be elliptical annular regions.

[0008] In some embodiments, the spacing between adjacent first annular regions is less than 1 mm.

[0009] In some embodiments, for any two adjacent first annular regions, the outer edge of the inner first annular region coincides with the inner edge of the outer first annular region.

[0010] In some embodiments, the cross-sectional area of ​​the light-converging structure parallel to the light-emitting surface gradually decreases in the direction away from the light-emitting surface.

[0011] In some embodiments, the cross-sectional shape of the light-converging structure perpendicular to the light-emitting surface is triangular, arc-shaped, or semi-arc-shaped.

[0012] In some embodiments, when the cross-sectional shape of the light-converging structure perpendicular to the light-emitting surface is triangular;

[0013] The plane containing the surface of the light-converging structure facing the center of the light-emitting surface has a first angle with the plane containing the light-emitting surface.

[0014] The plane containing the surface of the light-converging structure facing away from the center of the light-emitting surface has a second angle with the plane containing the light-emitting surface.

[0015] The first angle is greater than or equal to the second angle.

[0016] In some embodiments, all of the light-converging structures constitute a Fresnel lens structure.

[0017] In some embodiments, the refractive index of the light convergence structure is greater than or equal to the refractive index of the light guide plate body.

[0018] In some embodiments, the material of the light convergence structure is the same as the material of the light guide plate body.

[0019] In some embodiments, the light convergence structure is integrally formed with the light guide plate body.

[0020] Secondly, embodiments of this disclosure also provide a backlight module, including: a light guide plate as described above.

[0021] In some embodiments, it further includes: a prism sheet located on the light-emitting side of the light guide plate;

[0022] The prism sheet includes: a prism sheet body, the surface of the prism sheet body facing the light guide plate is a light incident surface, and the light incident surface is divided into a plurality of nested second annular regions, the center of all the second annular regions coincides with the center of the light incident surface;

[0023] Each of the second annular regions is provided with a corresponding prism structure. The orthographic projection of the light-converging structure on the light-emitting surface exactly covers the corresponding second annular region. The prism structure is used to limit the light-emitting angle of the corresponding second annular region.

[0024] In some embodiments, all of the second annular regions are circular annular regions;

[0025] Alternatively, all of the second annular regions may be elliptical annular regions.

[0026] In some embodiments, the spacing between adjacent second annular regions is less than 1 mm.

[0027] In some embodiments, for any two adjacent second annular regions, the outer edge of the inner second annular region coincides with the inner edge of the outer second annular region.

[0028] In some embodiments, the cross-sectional shape of the prism structure perpendicular to the light-emitting surface is an inverted triangle.

[0029] In some embodiments, the prism structure is made of the same material as the prism sheet body, and the prism structure and the prism sheet body are integrally formed.

[0030] Secondly, embodiments of this disclosure also provide a display device, including: a backlight module as described above. Attached Figure Description

[0031] Figure 1 A three-dimensional structural schematic diagram of a light guide plate provided in an embodiment of this disclosure;

[0032] Figure 2 A top view schematic diagram of a light guide plate provided in an embodiment of this disclosure;

[0033] Figure 3a for Figure 2 Schematic diagram of the cross section along line A-A';

[0034] Figure 3b for Figure 3a A schematic diagram of the optical path within the light guide plate shown in the image;

[0035] Figure 4 A top view schematic diagram of another light guide plate provided in an embodiment of this disclosure;

[0036] Figure 5 for Figure 4 Schematic diagram of the cross section along the B-B' direction;

[0037] Figure 6a A cross-sectional schematic diagram of another light guide plate provided in an embodiment of this disclosure;

[0038] Figure 6b A cross-sectional schematic diagram of another light guide plate provided in an embodiment of this disclosure;

[0039] Figure 7a A cross-sectional schematic diagram of another light guide plate provided in an embodiment of this disclosure;

[0040] Figure 7b A cross-sectional schematic diagram of another light guide plate provided in an embodiment of this disclosure;

[0041] Figure 8a A cross-sectional schematic diagram of another light guide plate provided in an embodiment of this disclosure;

[0042] Figure 8b A cross-sectional schematic diagram of another light guide plate provided in an embodiment of this disclosure;

[0043] Figure 9A cross-sectional schematic diagram of another light guide plate provided in an embodiment of this disclosure;

[0044] Figure 10 This is a cross-sectional schematic diagram of a backlight module provided in an embodiment of the present disclosure;

[0045] Figure 11 for Figure 10 The diagram shows the optical path within the backlight module.

[0046] Figure 12 A cross-sectional schematic diagram of another backlight module provided in an embodiment of this disclosure;

[0047] Figure 13 This is a bottom view of a prism sheet according to the present disclosure;

[0048] Figure 14 This is a bottom view schematic diagram of another type of prism sheet in this disclosure;

[0049] Figure 15 for Figure 14 Schematic diagram of the C-C' section. Detailed Implementation

[0050] To enable those skilled in the art to better understand the technical solutions of this disclosure, the light guide plate, backlight module and display device provided in this disclosure will be described in detail below with reference to the accompanying drawings.

[0051] Exemplary embodiments will be described more fully below with reference to the accompanying drawings; however, these exemplary embodiments may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will enable those skilled in the art to fully understand the scope of this disclosure.

[0052] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. As used herein, the singular forms “a” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It will also be understood that when the terms “comprising” and / or “made of” are used in this specification, the presence of the said feature, integral, step, operation, element, and / or component is specified, but the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or groups thereof is not excluded.

[0053] It will be understood that although the terms first, second, etc. may be used in this paper to describe various structures, these elements should not be limited to these terms, which are only used to distinguish one structure from another.

[0054] The embodiments described herein can be described with reference to plan views and / or cross-sectional views using the ideal schematic diagrams of this disclosure. Therefore, the example illustrations can be modified according to manufacturing techniques and / or tolerances. Therefore, the embodiments are not limited to those shown in the drawings, but include modifications to configurations formed based on manufacturing processes. Therefore, the areas illustrated in the drawings are schematic in nature, and the shapes of the areas shown in the figures illustrate specific shapes of areas of an element, but are not intended to be limiting.

[0055] Unless otherwise specified, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art. It will also be understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and this disclosure, and will not be interpreted as having an idealized or overly formal meaning, unless expressly so defined herein.

[0056] Existing privacy films (e.g., venetian blind-style privacy films) have relatively limited privacy angles, resulting in poor privacy protection. To address this technical problem, embodiments of this disclosure provide a light guide plate, a backlight module, and a display device.

[0057] Figure 1 This is a three-dimensional structural diagram of a light guide plate provided in an embodiment of the present disclosure. Figure 2 This is a top view schematic diagram of a light guide plate provided in an embodiment of this disclosure. Figure 3a for Figure 2 Schematic diagram of the cross section along line A-A'. Figure 3b for Figure 3a The schematic diagram of the optical path within the light guide plate shown is as follows: Figures 1-3b As shown, the light guide plate includes: a light guide plate body 1 and multiple light convergence structures 3 disposed on the light emitting surface 2 of the light guide plate body 1. The light emitting surface 2 of the light guide plate body 1 is pre-designed to be divided into multiple first annular regions, and the center of all the first annular regions coincides with the center O of the light emitting surface 2 of the light guide plate body 1. The multiple light convergence structures 3 correspond one-to-one with the multiple first annular regions. Each light convergence structure 3 is located within its corresponding first annular region, and the orthographic projection of each light convergence structure 3 on the light emitting surface 2 exactly covers its corresponding first annular region. The light convergence structure 3 is used to limit the light emission angle of the corresponding first annular region.

[0058] It should be noted that, Figure 1 The three-dimensional structure of the light guide plate shown only illustrates the structure of a certain area in the middle of the light guide plate, and does not represent the entire light guide plate.

[0059] The light guide plate body 1 in this disclosure can be a conventional light guide plate, and its material can be optical-grade acrylic material. Furthermore, the light incident method of the light guide plate body 1 can be direct-lit light incident (in which case no corresponding drawing is provided) or side-lit light incident (the light source 7 is located on the side of the light guide plate body 1). In the following description, the side-lit light incident method of the light guide plate body 1 will be used as an example for illustrative purposes, and the light incident method of the light guide plate body 1 will not limit the technical solution of this disclosure.

[0060] The light convergence structure 3 in this disclosure can be any structure capable of limiting the light emission angle. Those skilled in the art should understand that the light convergence structure 3 exemplified in the various embodiments of this disclosure are merely some optional or preferred implementations of this disclosure, and do not limit the technical solutions of this disclosure.

[0061] In this disclosure, the light convergence structure 3 is designed as a ring and multiple ring light convergence structures 3 are nested together, which can limit the light emission angle of the light-emitting surface 2 of the light guide plate in all directions, thereby enabling the backlight module to have the function of simultaneous privacy protection in all directions and improving the privacy protection effect.

[0062] Preferably, the refractive index of the light-converging structure 3 is greater than or equal to the refractive index of the light guide plate body 1, which can prevent total internal reflection of the light in the light guide plate body 1 at the interface between the light guide plate body 1 and the light-converging structure 3, thereby increasing the amount of light entering the light-converging structure 3 from the light guide plate body 1.

[0063] As one specific implementation, the light-converging structure 3 and the light guide plate body 1 are made of the same material, that is, they have the same refractive index, which can prevent total internal reflection of light within the light guide plate body 1 between them. More preferably, the light-converging structure 3 and the light guide plate body 1 are integrally formed, which can improve the overall robustness of the light guide plate.

[0064] As a preferred embodiment, all first annular regions are circular annular regions (see [reference]). Figure 1 As shown in the diagram, the privacy protection effect of the backlight module is relatively uniform in all directions. Of course, the first annular region in this disclosure can also be an annular region of other shapes, such as an elliptical annular region (no corresponding figure is given in this case) or other annular regions of regular / irregular shapes, which will not be listed here.

[0065] When designing multiple nested first annular regions, there may be a certain distance between adjacent first annular regions (the distance between the outer edge of the inner first annular region and the inner edge of the outer first annular region), or there may be no distance.

[0066] See Figure 1As shown in Figure 3, when there is a distance L1 between adjacent first annular regions, the larger the distance L1, the smaller the light-emitting area of ​​the light-emitting surface 2 of the light guide plate (within the light guide plate body 1, light will undergo total internal reflection in the area between adjacent first annular regions), which will affect the overall light-emitting brightness of the light-emitting surface 2. Therefore, in this disclosure, the distance L1 between adjacent first annular regions is less than 1 mm to ensure the overall light-emitting brightness of the light-emitting surface 2 of the light guide plate.

[0067] Figure 4 This is a top view schematic diagram of another light guide plate provided in an embodiment of this disclosure. Figure 5 for Figure 4 Schematic diagram of the B-B' section, and Figure 2 and Figure 3a The difference shown is that, in Figure 4 and Figure 5 In the light guide plate shown, for any two adjacent first annular regions, the outer edge of the inner first annular region coincides with the inner edge of the outer first annular region, that is, any two adjacent light convergence structures 3 are close together and there is no gap between them. At this time, the light emitting surface 2 of the light guide plate has the largest light emitting surface area.

[0068] As an alternative, the cross-sectional area of ​​the light-converging structure 3 parallel to the light-emitting surface 2 gradually decreases in the direction away from the light-emitting surface 2. The structure with this feature can limit the light emission angle; in the following sections, it will be described in detail with reference to several specific examples.

[0069] See Figure 2 and Figure 5 As shown, the cross-sectional shape of the light-converging structure 3 perpendicular to the light-emitting surface 2 is arc-shaped, that is, the light-converging structure 3 has three surfaces: a flat lower surface and two curved side surfaces. Both curved side surfaces show an upward convex trend. At this time, the two curved side surfaces can play the role of limiting the light-emitting angle. By adjusting the curvature of the two curved side surfaces, the range of the light-emitting angle can be adjusted.

[0070] Figure 6a A cross-sectional schematic diagram of another light guide plate provided in this embodiment of the present disclosure is shown below. Figure 6a As shown, unlike the previous embodiments, Figure 6a The cross-sectional shape of the light-converging structure 3 perpendicular to the light-emitting surface 2 is semi-arc-shaped, that is, the light-converging structure 3 has three surfaces: a flat lower surface, a strip-shaped annular side surface perpendicular to the flat lower surface, and a curved side surface. At this time, the strip-shaped annular side surface and the curved side surface can play the role of limiting the light-emitting angle. By adjusting the width of the strip-shaped annular side surface and / or the curvature of the curved side surface, the range of the light-emitting angle can be adjusted.

[0071] It should be noted that, Figure 6a The case shown, where there is a spacing L1 between adjacent semi-circular light convergence structures 3, is only for illustrative purposes.

[0072] Figure 6b A cross-sectional schematic diagram of another light guide plate provided in this disclosure embodiment is shown below. Figure 6b As shown, with Figure 6a The difference shown is that, Figure 6b There is no gap between any two adjacent ray convergence structures 3 with a semi-circular cross-section.

[0073] 7a is a cross-sectional schematic diagram of another light guide plate provided in an embodiment of this disclosure, as shown below. Figure 7a As shown, unlike the previous embodiments, Figure 7a The cross-sectional shape of the light-converging structure 3 perpendicular to the light-emitting surface 2 is triangular, that is, the light-converging structure 3 has three surfaces: a flat lower surface and two strip-shaped annular side surfaces.

[0074] Specifically, it is assumed that the plane containing the side of the light-converging structure 3 facing the center O of the light-emitting surface 2 has a first angle α, and the plane containing the light-emitting surface 2 has a second angle β. The range of the light-emitting angle can be adjusted by adjusting the magnitudes of the first angle α and / or the second angle β.

[0075] As a preferred embodiment, the first angle α is greater than or equal to the second angle β. In this case, all the light rays emitted from the side of the light-converging structure 3 tend to converge towards the central axis of the light guide plate, thereby further enhancing the privacy protection effect.

[0076] Figure 7b A cross-sectional schematic diagram of another light guide plate provided in this disclosure embodiment is shown below. Figure 7b As shown, with Figure 7a The difference shown is that, Figure 7b There is no gap between any two adjacent ray convergence structures 3 with triangular cross-sections.

[0077] Figure 8a A cross-sectional schematic diagram of another light guide plate provided in this disclosure embodiment is shown below. Figure 8a As shown, Figure 8a The scheme shown is based on Figure 7a A variation of the scheme shown; specifically, Figure 8aThe cross-sectional shape of the light-converging structure 3 perpendicular to the light-emitting surface 2 is triangular. The plane of the side of the light-converging structure 3 facing the center O of the light-emitting surface 2 is at a right angle with the plane of the light-emitting surface 2. The plane of the side of the light-converging structure 3 facing away from the center O of the light-emitting surface 2 is at an acute angle with the plane of the light-emitting surface 2.

[0078] Figure 8b A cross-sectional schematic diagram of another light guide plate provided in this disclosure embodiment is shown below. Figure 8b As shown, with Figure 8a The difference shown is that, Figure 8b There is no gap between any two adjacent light convergence structures 3 whose cross-sectional shape is a right triangle.

[0079] It should be noted that the cases in which the shapes and sizes of the light convergence structures within the same light guide plate shown in the above figures are identical are merely illustrative and do not limit the technical solutions of this disclosure. The shapes and sizes of the light convergence structures within the same light guide plate in this disclosure can be designed according to actual needs.

[0080] Figure 9 A cross-sectional schematic diagram of another light guide plate provided in this disclosure embodiment is shown below. Figure 9 As shown, in a preferred embodiment of this disclosure, all light-converging structures constitute a Fresnel lens structure. Figure 9 In the case shown, the cross-sectional shapes of different light convergence structures 3 in the light guide plate can be different (for example, the cross-sectional shape of some light convergence structures 3 is a right triangle, the cross-sectional shape of some light convergence structures 3 is a right trapezoid, and the cross-sectional shape of some light convergence structures 3 is an irregular shape), and the dimensions of different light convergence structures can be different.

[0081] exist Figure 9 In the light guide plate shown, the Fresnel lens structure formed by the light convergence structure 3 can not only limit the light output angle of each area, but also achieve the function of focusing light. That is, all the light emitted by the light guide plate tends to converge towards the central axis of the light guide plate (passing through the center O of the light output surface 2 of the light guide plate and perpendicular to the light output surface 2), thereby further improving the privacy protection effect.

[0082] It should be noted that, Figure 9 The illustration only shows one Fresnel lens structure and does not limit the technical solutions of this disclosure.

[0083] This disclosure provides a light guide plate that can limit the light emission angle of its light-emitting surface 2 in all directions, thereby enabling the backlight module to have the function of simultaneous privacy protection in all directions, thus improving the privacy protection effect.

[0084] Figure 10 This is a cross-sectional schematic diagram of a backlight module provided in an embodiment of the present disclosure. Figure 11 for Figure 10 The schematic diagram of the optical path within the backlight module is shown below. Figure 10 and Figure 11 As shown, the backlight module includes a light guide plate, which can be any of the light guide plates provided in the above embodiments. For a description of the light guide plate, please refer to the foregoing content, which will not be repeated here.

[0085] The backlight module in this embodiment also includes a prism sheet located on the light-emitting side of the light guide plate. The prism sheet includes a prism sheet body 4, the surface of the prism sheet body 4 facing the light guide plate is the light-incident surface 6, and the light-incident surface 6 is divided into multiple nested second annular regions. The center of all the second annular regions coincides with the center of the light-incident surface 6. Each second annular region is provided with a corresponding prism structure 5. The orthographic projection of the light-converging structure 3 on the light-emitting surface 2 exactly covers the corresponding second annular region. The prism structure 5 is used to limit the light-emitting angle of the corresponding second annular region (the emission angle of the light rays in the prism structure 5 when they exit from the interface between the prism structure 5 and the prism sheet body 4 and enter the prism sheet body 4).

[0086] In this disclosure, by setting the aforementioned prism sheet on the light-emitting side of the light guide plate, the light emission angle of the light emitted from the light guide plate can be further limited, that is, the viewing angle of the backlight module can be further reduced to improve the privacy protection effect.

[0087] Optionally, the cross-sectional shape of the light-emitting surface 2 of the prism structure 5, which is perpendicular to the light guide plate body, is an inverted triangle. In this disclosure, the inverted triangle prism structure 5 is arranged in a ring on the light-incident surface 6 of the prism body 4. When the light emitted from the light guide plate passes through the inverted triangle prism structure 5, it will converge from all sides toward the central axis of the prism body (passing through the center of the prism body 4 and perpendicular to the light-incident surface 6 of the prism body 4), regardless of the position of the light source 7. That is, the light source 7 can be placed on the PCB board side of the backlight module. In this way, there is no need to add a module frame to the existing backlight module (side-incident light), and the effect of light converging toward the center can be achieved to achieve privacy protection.

[0088] In the aforementioned prism sheet, the material of the prism sheet body 4 can be a conventional prism sheet material, such as acrylic resin. The material of the prism structure 5 can be the same as or different from the material of the prism sheet body 4. When selecting the materials for the prism structure 5 and the prism sheet body 4, preferably, the refractive index of the prism structure 5 is less than or equal to the refractive index of the prism sheet body 4. This avoids total internal reflection of light within the light guide plate prism structure 5 at the interface between the prism structure 5 and the prism sheet body 4, thereby increasing the amount of light incident from the prism structure 5 to the prism sheet body 4 and improving light transmittance. As an optional solution, the prism structure 5 is made of the same material as the prism sheet body, and the two are integrally formed.

[0089] Figure 12 A cross-sectional schematic diagram of another backlight module provided in this disclosure embodiment is shown below. Figure 12 As shown, the light guide plate in this backlight module is Figure 9 The light guide plate shown, in which all the light convergence structures are formed by the light guide plate, constitutes a Fresnel lens structure, which makes all the light emitted from the backlight module converge toward the center to improve the privacy protection effect.

[0090] Figure 13 This is a bottom view schematic diagram of a prism sheet according to the present disclosure, as shown below. Figure 13 As shown, as an optional solution in this disclosure, all second annular regions are circular annular regions, in which case the privacy protection effect of the backlight module is relatively uniform in all directions. Of course, the second annular region in this disclosure can also be annular regions of other shapes, such as elliptical annular regions (no corresponding figure is given in this case) or other regular / irregular annular regions, which will not be listed here.

[0091] When designing multiple nested second annular regions, there may be a certain distance between adjacent second annular regions (the distance between the outer edge of the inner second annular region and the inner edge of the outer second annular region), or there may be no distance.

[0092] See Figure 13 As shown, when there is a gap L2 between adjacent second annular regions, some of the light emitted from the light guide plate will directly enter the prism sheet body 4 through this gap L2 (without passing through the prism structure 5). The emission angle of this portion of light will not be further limited by the prism structure 5, thus affecting the overall privacy protection effect of the backlight module. The larger the gap L2, the smaller the area on the prism sheet that can further limit the emission angle of the light, and the weaker the overall privacy protection effect of the backlight module. Therefore, in this disclosure, the gap L2 between adjacent second annular regions is less than 1mm to ensure the overall privacy protection effect of the backlight module.

[0093] Figure 14This is a bottom view schematic diagram of another type of prism sheet in this disclosure. Figure 15 for Figure 14 A schematic diagram of the C-C' section is shown below. Figure 14 and Figure 15 As shown, with Figure 10 , Figure 12 and 13 The difference shown is that, in Figure 14 and Figure 15 The prism sheet shown has the following characteristics: for any two adjacent second annular regions, the outer edge of the inner second annular region coincides with the inner edge of the outer second annular region. That is, any two adjacent annular prism structures 5 are close together and there is no gap. At this time, the prism sheet can limit the light output angle of the incident light at each position, and the overall privacy protection effect of the backlight module is optimal.

[0094] This disclosure provides a backlight module that has the function of simultaneously preventing peeping from all directions, thereby improving the anti-peeping effect.

[0095] This disclosure also provides a display device, which includes a backlight module. The backlight module adopts the backlight module provided in the foregoing embodiments. For a description of the backlight module, please refer to the foregoing content, and it will not be repeated here.

[0096] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of this disclosure, and this disclosure is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of this disclosure, and these modifications and improvements are also considered to be within the scope of protection of this disclosure.

Claims

1. A backlight module, characterized in that, The light source, the light guide plate and the prism sheet; The light guide plate comprises a light guide plate body having a light exit surface, and a plurality of first annular regions are divided on the light exit surface, and the centers of all the first annular regions coincide with the center of the light exit surface; Each of the first annular regions is provided with a corresponding light converging structure, the orthographic projection of the light converging structure on the light exit surface exactly covers the corresponding first annular region, and the light converging structure is used for limiting the light exit angle of the corresponding first annular region; the cross-sectional shapes of different light converging structures are different, wherein the cross-sectional shape of part of the light converging structures is a right triangle, the cross-sectional shape of part of the light converging structures is a right trapezoid, and the angle between the plane where the side surface of the light converging structure facing the center of the light exit surface is located and the plane where the light exit surface is located is a right angle; The refractive index of the light converging structure is greater than or equal to the refractive index of the light guide plate body; The prism sheet comprises a prism sheet body, the surface of the prism sheet body facing the light guide plate is a light entrance surface, a plurality of second annular regions are divided on the light entrance surface, and the centers of all the second annular regions coincide with the center of the light entrance surface; each of the second annular regions is provided with a corresponding prism structure, the orthographic projection of the light converging structure on the light exit surface exactly covers the corresponding second annular region, and the prism structure is used for limiting the light exit angle of the corresponding second annular region; The orthographic projection of one of the prism structures and one of the converging structures on the light guide plate overlaps; The converging structure has a first vertex, the distance between the first vertex and the prism sheet body is not greater than the distance between other positions of the converging structure and the prism sheet body; the prism structure has a second vertex, the distance between the second vertex and the light guide plate body is not greater than the distance between other positions of the prism structure and the light guide plate body; The refractive index of the prism structure is less than or equal to the refractive index of the prism sheet body; The light source is located on the side surface of the light guide plate body.

2. The backlight module of claim 1, wherein, All the first annular regions are circular annular regions; Or, all the first annular regions are elliptical annular regions.

3. The backlight module of claim 1, wherein, The distance between adjacent first annular regions is less than 1 mm.

4. The backlight module of claim 1, wherein, For any two adjacent first annular regions, the outer edge of the first annular region on the inner side coincides with the inner edge of the first annular region on the outer side.

5. The backlight module of claim 1, wherein, The cross-sectional area of the light converging structure parallel to the light exit surface gradually decreases in the direction away from the light exit surface.

6. The backlight module of claim 1, wherein, All the light converging structures constitute a Fresnel lens structure.

7. The backlight module of any one of claims 1-6, wherein, The material of the light converging structure is the same as that of the light guide plate body.

8. The backlight module of claim 7, wherein, The light converging structure and the light guide plate body are integrally formed.

9. The backlight module of claim 1, wherein, All the second annular regions are circular annular regions; Or, all the second annular regions are elliptical annular regions.

10. The backlight module of claim 1, wherein, The distance between adjacent second annular regions is less than 1 mm.

11. The backlight module of claim 1, wherein, For any two adjacent second annular areas, the outer side edge of the second annular area located at the inner side coincides with the inner side edge of the second annular area located at the outer side.

12. The backlight module of claim 1, wherein, The cross-sectional shape of the prism structure perpendicular to the light-out surface is inverted triangle.

13. The backlight module of claim 1, wherein, The material of the prism structure is the same as that of the prism sheet body, and the prism structure is integrally formed with the prism sheet body.

14. A display device comprising: Comprising: The backlight module according to any one of claims 1-13.

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