Lens, backlight module and interactive panel

Abstract

The utility model discloses a lens, backlight module and interactive panel, mainly relate to optical element technical field, the lens includes the lens main part, and the bottom and top of lens main part respectively form the light incident surface and light emergent surface, and the light incident surface and light emergent surface are set to be free-form surface; at least four total reflection surfaces are arranged on the periphery of the lens body, the two sides of each total reflection surface are connected with the light inlet surface and the light outlet surface respectively, and the included angle between each total reflection surface and a target plane is set to be 90-110 degrees. According to the lens, the free-form surfaces are used as the light-in surface and the light-out surface, so that light from different angles can smoothly enter the lens main body, and the loss of the light in the entering process is effectively reduced. The total reflection surface is matched with the light emitting surface to further restrain the shape of the light spot, so that the shape of the light spot can be matched with the screen shape of corresponding display equipment or the layout mode of the light source, the shape of the light spot is more regular, and the edge is clearer.

Description

Technical Field

[0001] This utility model relates to the technical field of optical components, and in particular to a lens, a backlight module, and an interactive flat panel. Background Technology

[0002] In recent years, with the continuous advancement of display technology, Mini LED, as an emerging screen backlight technology, has gradually entered the public eye and received widespread attention. Mini LED backlight technology increases the number of backlight areas, enabling each backlight area to control its brightness more precisely, thereby significantly improving the contrast of the picture and correspondingly enhancing the picture quality of the display device, resulting in a more refined and outstanding overall image.

[0003] However, despite the significant advantages of Mini LED backlighting technology in improving image quality, several issues remain to be addressed. One prominent problem is the "halo" effect. The halo effect refers to the phenomenon where bright areas of a display panel are affected by light from bright areas, causing backlight from the bright areas to diffuse into the darker areas, creating a "halo" effect. This halo is essentially a display artifact that severely impacts the visual experience and quality of the image. It is particularly prevalent in display panels that support local dimming, making it a significant factor hindering the further development of Mini LED backlighting technology. Utility Model Content

[0004] The purpose of this utility model embodiment is to provide a lens, a backlight module, and an interactive flat panel, which can solve the above-mentioned problems existing in the prior art.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] In a first aspect, a lens is provided, comprising:

[0007] The lens body has an incident light surface and an exit light surface formed at its bottom and top, respectively, and both the incident light surface and the exit light surface are freeform surfaces. A total reflection surface is provided around the outer periphery of the lens body. The total reflection surface is located between the incident light surface and the exit light surface. The two sides of the total reflection surface are connected to the incident light surface and the exit light surface, respectively. The included angle between each total reflection surface and the target plane is set to 90°-110°.

[0008] By utilizing the total reflection surface surrounding the lens body, the shape of the light-emitting surface edge can be determined according to the desired light spot shape, making the light spot edge clearer, significantly improving the sharpness of the light spot edge, and increasing the contrast between the center area and the edge area of ​​the light spot.

[0009] As an optional implementation, any two adjacent total reflection surfaces are connected by a chamfered bevel, wherein the chamfered bevel is at the same angle as the two adjacent total reflection surfaces.

[0010] By using a chamfered bevel to further define the edge shape of the light-emitting surface, the problem of light scattering at the corners of the light spot is effectively suppressed, making the overall shape of the light spot closer to the target shape.

[0011] As an optional implementation, the width of the chamfered bevel is set to 0.5mm-1.5mm.

[0012] As an optional implementation, the overall length and overall width of the lens body are both set to be less than 8mm.

[0013] As an optional implementation, the overall height of the lens body is set to be less than 6mm.

[0014] As an optional implementation, both the light-incident surface and the light-exit surface are configured as spherical surfaces.

[0015] As an optional implementation, the curvature of the light-incident surface is set to be smaller than the curvature of the light-exiting surface.

[0016] As an optional implementation, the total reflection surface is configured to be four.

[0017] Secondly, a backlight module is provided, comprising:

[0018] The back panel has multiple light sources arranged in a matrix.

[0019] Multiple lenses as described in the first aspect are respectively disposed on each of the light sources.

[0020] As an optional implementation, each of the light sources is configured as an LED chip.

[0021] Thirdly, an interactive flat panel is provided, comprising:

[0022] The backlight module as described in the second aspect.

[0023] The beneficial effects of this utility model are as follows: the lens uses a freeform surface as the light-incident surface and the light-outceasing surface, which allows light from different angles to smoothly enter the lens body, effectively reducing the loss of light during the entry process. At the same time, the light-outceasing surface can also accurately control the light inside the lens body, thereby further improving the utilization rate of light, realizing effective constraint on the light emission direction, and ensuring efficient transmission and distribution of light inside the lens.

[0024] The lens body is surrounded by total internal reflection surfaces. Light rays inside the lens body are reflected by each of these surfaces, ensuring that all light rays, after multiple reflections, are emitted through the light-emitting surface in a more uniform and orderly manner. The specific number of total internal reflection surfaces can be flexibly adjusted according to actual needs. Together with the light-emitting surface, this further constrains the shape of the light spot, allowing it to match the screen shape of the corresponding display device or the layout of the light source. This results in a more regular light spot shape with clearer edges, significantly improving the uniformity and brightness consistency of the light spot, and providing users with a more delicate and realistic visual experience. Attached Figure Description

[0025] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0026] Figure 1 This is a schematic diagram of the light spot of a conventional lens as described in an embodiment of this utility model;

[0027] Figure 2 This is a waveform diagram of the brightness of a conventional lens as described in an embodiment of this utility model;

[0028] Figure 3 This is one of the schematic diagrams of the overall structure of the lens described in this utility model embodiment;

[0029] Figure 4 This is a front view of the lens described in an embodiment of the present invention;

[0030] Figure 5 This is a second schematic diagram of the overall structure of the lens according to an embodiment of the present utility model;

[0031] Figure 6 A cross-sectional view of the lens described in this embodiment of the utility model;

[0032] Figure 7 This is a top view of the lens described in an embodiment of the present utility model;

[0033] Figure 8 This is a schematic diagram of the lens spot according to an embodiment of the present invention;

[0034] Figure 9 This is a waveform diagram of the lens brightness according to an embodiment of the present invention.

[0035] In the diagram: 10. Lens body; 11. Light entrance; 111. Light entrance surface; 12. Light exit surface; 13. Total internal reflection surface; 14. Chamfered bevel. Detailed Implementation

[0036] To make the technical problems solved by this utility model, the technical solutions adopted, and the technical effects achieved clearer, the technical solutions of the embodiments of this utility model are further described in detail below. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0037] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0038] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0039] Mini LED technology is an emerging display backlight technology that has gradually entered the public eye and received widespread attention in recent years with the continuous innovation of display technology. Mini LED backlight technology refers to the use of smaller LED chips as backlight sources. Compared with traditional LED backlight technology, Mini LED technology increases the number and precision of backlight areas, enabling each backlight area to control its brightness more precisely, thereby significantly improving the contrast of the picture and the picture quality of the display device, resulting in a more refined and excellent overall image quality.

[0040] In Mini LED backlight technology, the main function of the lens is to optimize the light propagation path and improve light utilization and uniformity. Specifically, lenses are typically designed with specific shapes and refractive indices to refract and focus light. In Mini LED backlight modules, lenses are usually mounted above the LED chips. When the LED chip emits light, the light first enters the incident surface of the lens, then undergoes refraction and focusing within the lens before exiting from the emitting surface. The lens design not only affects the direction of light propagation but also determines the shape and size of the light spot. By adjusting the lens's shape and refractive index, precise control of the light spot shape can be achieved, thus meeting the light distribution requirements of different display devices.

[0041] However, despite the significant advantages of Mini LED backlighting technology in improving picture quality, some issues remain to be addressed. One prominent problem is the "halo effect," which refers to the phenomenon where dark areas of the display panel are affected by the light from brighter areas, such as... Figures 1-2 The images shown are simulated views of the light spot formed by the lens in traditional technology, as well as brightness waveforms that illustrate the main cause of the "halo" effect. It can be seen that a significant floodlight area forms around the main light spot. This is primarily due to the gradual decrease in brightness at the periphery of the light emitted from the lens, causing the bright backlight to flood into the dark areas with low edge sharpness, thus creating the "halo" phenomenon. This "halo" is essentially a display artifact that severely affects the visual experience and quality of the image. The "halo" effect is particularly pronounced in display panels that support local dimming, making it a significant factor hindering the further development of Mini LED backlight technology.

[0042] In view of this, the present invention provides a lens in which the number and manner of the total reflection surfaces surrounding the lens body can be adjusted according to the arrangement of the lens in the backlight module and the screen shape of the display device to which the backlight module is applied, so that the light emitted from the light-emitting surface of the lens can form a light spot with a matching shape and sharp edges on the screen of the relevant device, thereby effectively solving the technical problem of the serious "halo" effect in the application of backlight technology in display devices.

[0043] Please refer to the instruction manual attached. Figures 3-6The lens mainly comprises a lens body 10, which serves as the supporting foundation for the lens. The bottom and top of the lens body 10 respectively form an incident surface 111 and an exit surface 12, both of which are freeform surfaces. The primary function of the incident surface 111 is to receive and guide light emitted from the light source into the lens. The freeform surface design effectively matches the divergence characteristics of the light source, reducing reflection and scattering of light on the incident surface 111 side, and improving the efficiency of light entering the lens body 10. It is worth noting that although both the exit surface 12 and the incident surface 111 are freeform surfaces, the curvature and radius of the exit surface 12 may differ from those of the incident surface 111. This allows for the constraint of the light emission direction through different freeform surface structures. Generally, the exit surface 12 provides a smoother light transition, reducing abrupt changes and scattering of light as it leaves the lens.

[0044] In backlight module applications, freeform surfaces are configured to freely distribute light intensity, control light angle and optical path difference, thereby meeting specific lighting requirements and greatly improving energy efficiency. For example, in LED lighting systems, designing a freeform surface lighting system can improve light distribution, increase energy efficiency, and achieve uniform illuminance.

[0045] Furthermore, a total reflection surface 13 is provided around the outer periphery of the lens body 10. The total reflection surface 13 is located between the light-incident surface 111 and the light-exit surface 12. The two sides of the total reflection surface 13 are connected to the light-incident surface 111 and the light-exit surface 12, respectively. The function of the total reflection surface 13 in this lens is to guide the light to undergo total internal reflection and converge to the central region of the lens body 10. In some embodiments, the lens body 10 is typically provided with at least four total reflection surfaces 13. The number and layout of the total reflection surfaces 13 can be determined according to the design requirements and application scenarios of the lens. For example, in the backlight module where the lens is used, where the light source is arranged in a matrix (and the screen of the related display device is also set as a rectangle), there can be four total reflection surfaces 13. The four total reflection surfaces 13 surround the outer periphery of the lens body 10 in a rectangular shape. Thus, under the constraint of each total reflection surface 13, the light spot formed by the light emitted from the light-emitting surface 12 can form a shape that is close to the shape of the layout of each total reflection surface 13. Therefore, this embodiment does not have strict limitations or requirements on the number and layout of the total reflection surfaces 13.

[0046] As can be understood, total internal reflection (also known as total internal reflection) refers to the phenomenon where light traveling from an optically denser medium (i.e., a medium with a higher refractive index) to an optically less dense medium (i.e., a medium with a lower refractive index) is completely reflected back into the original medium. For total internal reflection to occur, two conditions must be met simultaneously: first, the light must travel from an optically denser medium to an optically less dense medium; second, the angle of incidence must be greater than or equal to the critical angle. Therefore, in this embodiment, the angle between the total reflection surface 13 and the target plane is set to 90°-110°. The target plane is defined as the plane used to install the light source, ensuring that the lens is always installed above the light surface in the application of the backlight module, so that the light can be reflected and converged according to the predetermined path. In this way, the light rays from the light source to any total reflection surface 13 can meet the above conditions, so that the light rays entering the lens body 10 and directed to the total reflection surface 13 can converge and converge in the central area of ​​the lens through the total reflection surface 13, achieving the effect of finally exiting the lens from the light-emitting surface 12. This not only improves the light utilization efficiency, but also enables the lens to adapt to different application scenarios and the light emission characteristics of the light source.

[0047] It should also be noted that the material of the lens body 10 is usually an optical material with high light transmittance, low refractive index and good processing performance, such as optical grade PMMA (polymethyl methacrylate) or PC (polycarbonate). This can ensure that the loss of light during the transmission process inside the lens body 10 is minimized, while improving the durability and anti-aging performance of the lens.

[0048] In summary, the lens provided by this utility model, through the aforementioned series of structural designs, effectively improves light management efficiency and the ability to constrain the shape of the light spot. Specifically, the lens employs freeform surfaces as the incident surface 111 and the exit surface 12, greatly expanding the adaptability of light incidence. This allows light from different angles to enter the lens body 10 more smoothly, effectively reducing light loss during the entry process. The freeform exit surface 12 enables precise control of the light exit angle, further improving light utilization and ensuring efficient light transmission and distribution. This significantly reduces flooding around the light spot formed after refraction through the lens, alleviating the "halo" effect and improving the sharpness of the light spot's periphery. Consequently, in applications such as backlight modules and display devices, the lens exhibits less influence between adjacent backlight areas, resulting in higher contrast and superior display performance.

[0049] The total reflection surfaces 13 arranged on the outer periphery of the lens body 10 can not only be flexibly adjusted according to actual needs, making the lens solution more versatile, but their design also ensures that all light rays can be emitted more evenly through the light-emitting surface 12 after multiple reflections by the total reflection surfaces 13, thereby improving light utilization and illumination uniformity. For example, after the light emitted from the light source enters the lens body through the light-incident surface 111, part of the light will directly pass through the lens body and be directed towards the light-emitting surface. This part of the light can be refracted at a small angle by the light-emitting surface 12 and projected onto the target object (such as the light guide plate of the backlight module) while maintaining its original direction. The other part of the light will be directed towards any total internal reflection surface 13 and re-enter the lens body under the reflection of the total internal reflection surface 13. If the angle between this part of the light and the light-emitting surface 12 is larger, it will be further reflected by the light-emitting surface 12. Thus, after multiple reflections inside the lens, the light finally passes through the light-emitting surface 12 at a smaller angle and exits from the light-emitting surface 12. This design not only effectively constrains the shape of the light spot but also makes the shape of the light spot more regular and the edges clearer. It also significantly improves the uniformity and brightness consistency of the light spot, bringing users a more delicate and realistic visual experience.

[0050] Please continue to refer to the instruction manual appendix. Figures 3-5 , Figure 7 To further effectively constrain the light spot formed by the lens, any two adjacent total reflection surfaces 13 are connected by a chamfered bevel 14. The chamfered bevel 14 has an equal angle with each of the two adjacent total reflection surfaces 13, ensuring that the cross-sectional shape of the lens body is at least octagonal. In this embodiment, the chamfered bevel 14 is set as a plane, the purpose of which is to constrain the light spot at the junction of any two adjacent total reflection surfaces 13 of the light-emitting surface 12, thereby allowing the light spot shape to further approach the target shape.

[0051] It is important to understand that the general shape of the light spot is constrained by the total internal reflection surface 13, such as 7. Figure 9 As shown in the attached diagram, in an embodiment where the light spot shape needs to be constrained to approximately a square, there are four total reflective surfaces 13, each with the same size. However, if a structure of multiple total reflective surfaces 13 connected directly is adopted, the light-emitting surface 12 will form a right-angle structure at the junction of the total reflective surfaces 13. Because the angle of this right-angle structure is relatively small, the light constraint strength at the junction of the total reflective surfaces 13 will be weakened, and the light-emitting surface 12 will experience significant scattering at this point, which is detrimental to the constraint of the light spot shape. By setting chamfered bevels 14 between the total reflective surfaces 13, the angle between the chamfered bevels 14 and the total reflective surfaces 13 is increased, thereby alleviating the light scattering problem at the corner of the light-emitting surface 12, making the light spot shape closer to the ideal state, and improving the final display effect in the backlight module application.

[0052] It should be noted that the angle between each chamfered bevel 14 and the target plane is also set to 90°-110° to ensure that the chamfered bevel 14 can reflect the light inside the lens body and ensure that the light can finally be emitted from the light-emitting surface 12, thus ensuring the light utilization rate of the lens.

[0053] Based on the above structural description of the chamfered bevel 14, in one embodiment, the width of the chamfered bevel 14 is set to 0.5mm-1.5mm. While ensuring that the total reflection surfaces 13 are connected by the chamfered bevel 14, the width of the chamfered bevel 14 is kept as small as possible. This allows the light-emitting surface 12 to have a floodlight constraint effect at the corner of any two total reflection surfaces 13 without significantly changing the overall shape of the light spot, thus meeting the application requirements in relevant display devices.

[0054] Under the structure of this implementation, such as Figure 8 As shown in the figure, region A exhibits a significant drop in brightness; the brightness of the outer edge of the light spot is considerably weaker than that of the central spot. Figure 9 As can be seen in region B, there is no obvious spot around the periphery. Furthermore, region C at the corner of the spot effectively suppresses outward-scattered light, allowing the overall spot to conform as closely as possible to the cross-sectional shape of the lens.

[0055] Based on any of the above embodiments, the overall length and width of the lens body 10 are both set to be less than 8mm, so that the size of the lens can meet the dense arrangement requirements of the Mini LED chips, and facilitate the installation and layout of the lens device in the backlight module.

[0056] The overall height of the lens body 10 is set to be less than 6mm, thereby reducing the thickness space occupied by the lens in the application of the backlight module, thus improving the compactness and reliability of the entire backlight module.

[0057] Please refer to the instruction manual attached. Figure 6 In one embodiment, the light-incident surface 111 and the light-exit surface 12 located on both sides of the lens body are both set as spherical surfaces. The spherical light-incident surface 111 and the light-exit surface 12 can provide the required optical performance, realize the precise control and convergence of light, and make the light spot effect formed by the lens more uniform, so as to achieve the expected imaging effect.

[0058] In addition, the manufacturing process of spherical surfaces is simpler than that of other irregular freeform surfaces, making them easier to process and inspect. This reduces manufacturing costs and minimizes performance differences between different batches of lenses, ensuring product consistency and reliability. As a result, lenses are more cost-effective in mass production and application.

[0059] When both the light-incident surface 111 and the light-exit surface 12 are spherical, the curvature of the light-incident surface 111 is set to be smaller than that of the light-exit surface 12. This ensures that light can pass through the light-incident surface 111 and enter the lens, while also enhancing the lens's ability to converge light. Specifically, in backlight modules and related display devices, light emitted from the light source enters the lens after passing through the light-incident surface 111, and is then refracted at the light-exit surface 12. The larger curvature of the light-exit surface 12 causes the refracted light to be more concentrated at a point or in a certain area, thereby improving the lens's converging effect and reducing flooding at the edges of the light-exit surface 12.

[0060] This embodiment also provides a backlight module. It is understood that the backlight module is one of the key components of a liquid crystal display (LCD), and its main function is to provide sufficient brightness and a uniformly distributed light source so that the LCD can display images normally.

[0061] Generally, a backlight module consists of components such as a backplate, light source, light guide plate, and optical films. The backplate serves as the supporting foundation for the backlight module. In display device applications, the backplate is installed at the rear of the display device to protect its internal components. The light source provides the light needed to illuminate the LCD panel; therefore, multiple light sources are arranged in a matrix on the backplate to control the backlight area. The light guide plate guides the direction of light scattering, improving panel brightness and ensuring brightness uniformity. Optical films further enhance the display effect by improving light distribution and uniformity. In addition, the backlight module of this embodiment also includes a plurality of lenses as described in any of the above embodiments. Each lens has a light inlet 11 on one side for forming the light inlet surface 111. The size of the light inlet 11 is set to accommodate the light source, and the inner wall of the light inlet 11 forms the light inlet surface 111. When the plurality of lenses are respectively disposed on each light source, each light source can be covered by the lens, so that the light emitted by each light source can be refracted and modulated by the corresponding lens and then projected onto the corresponding area of ​​the light guide plate.

[0062] In one embodiment, each light source in the backlight module is configured as an LED lamp, specifically a Mini LED lamp, to meet the backlight requirements of the corresponding display device.

[0063] Furthermore, this embodiment also provides an interactive flat panel, which includes the backlight module provided in the above embodiment, and on this basis, the interactive flat panel also includes a display screen, which can be mounted and cooperated with the back plate in the backlight module through a frame.

[0064] It should be noted that in practical applications, interactive flat panels can operate the content displayed on the screen and achieve human-computer interaction through capacitive touch technology and electromagnetic induction technology. They integrate one or more functions such as a projector, whiteboard, screen, audio system, television, and video conferencing terminal. Specifically, the hardware of an interactive flat panel consists of a touch module, a display module, and an intelligent processing system, all integrated together by a unified structural component and supported by a dedicated software system. The display module and touch module work together to achieve display and touch functions. Users can operate the display screen using their fingers or a stylus. The intelligent processing system generates handwriting based on the user's touch input and displays it on the screen, or generates control operations based on the user's touch input to process the displayed content.

[0065] Typically, interactive flat panels are equipped with at least one operating system, including but not limited to Android, HarmonyOS, Linux, and Windows. The operating system processes touch input received through the display screen. Interactive flat panels can have at least one application installed on their operating system, such as a whiteboard application. This whiteboard application can be a built-in application of the operating system or an application downloaded from a third-party device or server.

[0066] In summary, by adopting the backlight module provided by the above-described embodiments, especially when the backlight module uses a Mini LED light source, the regional light control accuracy and the final effect are improved due to the lens significantly improving the "halo" effect of the light spot, which significantly enhances the contrast of the interactive flat panel between different backlight areas, ultimately bringing users a more delicate and realistic visual experience.

[0067] In the description herein, it should be understood that the terms "upper," "lower," "left," "right," and other orientations or positional relationships are used only for ease of description and simplification of operation, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first" and "second" are merely used for distinction in description and have no special meaning.

[0068] In the description of this specification, references to terms such as "an embodiment," "example," etc., 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, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0069] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style of the specification is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0070] The technical principles of this utility model have been described above with reference to specific embodiments. These descriptions are merely for explaining the principles of this utility model and should not be construed as limiting the scope of protection of this utility model in any way. Based on this explanation, those skilled in the art can readily conceive of other specific embodiments of this utility model without any inventive effort, and these embodiments will all fall within the scope of protection of this utility model.

Claims

1. A lens characterized by, The application relates to a lens body (10), the bottom and the top of the lens body (10) are respectively formed with an entrance light surface (111) and an exit light surface (12), the entrance light surface (111) and the exit light surface (12) are both set as free curved surfaces; the outer periphery of the lens body (10) is provided with total reflection surfaces (13), the total reflection surfaces (13) are located between the entrance light surface (111) and the exit light surface (12), the two sides of the total reflection surfaces (13) are respectively connected with the entrance light surface (111) and the exit light surface (12), and the included angle between each total reflection surface (13) and a target plane is set as 90-110 degrees. Any two adjacent total reflection surfaces (13) are connected through chamfered inclined surfaces (14), the chamfered inclined surfaces (14) are respectively equal to the included angles between the two adjacent total reflection surfaces (13).

2. The lens of claim 1, wherein The width dimension of the chamfered inclined surface (14) is set as 0.5-1.5 mm.

3. The lens of claim 2, wherein The overall length and the overall width dimension of the lens body (10) are both set as less than 8 mm.

4. The lens of claim 1, wherein The overall height dimension of the lens body (10) is set as less than 6 mm.

5. The lens of claim 1, wherein The entrance light surface (111) and the exit light surface (12) are both set as spherical surfaces.

6. The lens of any one of claims 1-5, wherein, The curvature of the entrance light surface (111) is set as less than the curvature of the exit light surface (12).

7. The lens of claim 6, wherein The total reflection surfaces (13) are set as four.

8. The lens of claim 1, wherein The application relates to a backlight module.

9. A backlight module, characterized in that, A back plate is provided with a plurality of light sources arranged in a matrix mode; A plurality of lenses according to any one of claims 1-8 are respectively arranged on the light sources. Each light source is set as an LED chip.

10. The backlight module of claim 9, wherein, The application relates to a backlight module.

11. An interactive whiteboard, comprising: The backlight module according to any one of claims 9-10. ​

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