Side-illuminated backlight module with light leakage prevention function and display device

Abstract

A backlight module and a display device including the backlight module are provided, which improve light output uniformity and optical quality. [Solution] The backlight module includes a backplate, a light guide plate (22), a light source (23), and a sleeve attached to the backplate. The sleeve penetrates the light guide plate in its axial direction. The light guide plate has a plurality of microstructures (222), and the light guide plate has a blank area (D0) where the sleeve is installed and a first area (D10) surrounding the blank area. The first area has at least one high-density area (D11) and one low-density area (D12). The blank area is free of microstructures and is located between the at least one high-density area and the light-incident edge (221) of the light guide plate. The distribution density of the microstructures in the high-density area is greater than the average distribution density of the microstructures in the low-density area. By adjusting the distribution of the microstructures according to the distance from the light source, shadows caused by the installation of the sleeve can be overcome and the light output uniformity across the entire light-emitting surface can be improved.

Description

[Technical Field]

[0001] This application claims priority from a Chinese patent application bearing application number 202510279868.8, filed on March 10, 2025, and entitled "Side-illuminated backlight module and display device with light leakage prevention function," the entire contents of which are hereby incorporated by reference into this application.

[0002] The present invention relates to an optical device, and more particularly to a backlight module and a display device. [Background technology]

[0003] Driver distraction and fatigue are important causes of unexpected vehicle accidents, and a Driver Monitoring System (DMS) can add multiple lines of defense to driving safety. Driver monitoring systems are fitted with lenses on the dashboard to monitor and detect the driver's behavior and physiological state by collecting the driver's facial movement characteristics, such as eye blinks, gaze direction, and head movement. If the driver monitoring system detects abnormal data, it issues a warning signal and activates the driver assistance system, thereby improving driving safety and reducing the accident rate.

[0004] When the lens is attached to the dashboard, how to balance the imaging viewing angle of the lens and the optical quality of the dashboard is a goal that those skilled in the art need to strive for urgently. Summary of the Invention [Problem to be solved by the invention]

[0005] SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a backlight module that improves light output uniformity and optical quality. [Means for solving the problem]

[0006] The backlight module of the present invention includes a backplate, a light guide plate mounted on the backplate and having at least one light incident side, a light source mounted on the at least one light incident side, and a sleeve mounted on the backplate. The sleeve axially penetrates the light guide plate. The light guide plate has a plurality of microstructures, the light guide plate having a blank area where the sleeve is formed and a first area surrounding the blank area, the blank area having no microstructures, the first area having at least one high-density area and a low-density area, the blank area being located between the at least one high-density area and the light incident side, the distribution density of the microstructures in the high-density area being greater than the average distribution density of the microstructures in the low-density area, the distribution density of the microstructures in the low-density area gradually increasing in a direction away from the at least one light incident side, and the distribution density of the microstructures in the high-density area gradually decreasing in a direction away from the at least one light incident side.

[0007] Another technical solution of the present invention is that the at least one high-density area is located in the extension direction of a line connecting the at least one light-entering edge and the blank area.

[0008] Another technical solution of the present invention is that the light guide plate has two light incident sides, the first region has two high-density regions, each of which corresponds to a light incident side that is far away, and the blank region is located between each of the high-density regions and the corresponding light incident side.

[0009] Another technical means of the present invention is that the blank area is located between the two light incident sides, and the distance between the blank area and the two light incident sides is equal, and the distance between the area with the highest microstructure distribution density in the low-density area and the two light incident sides is equal.

[0010] Another technical means of the present invention is that the blank area is located between the two light incident sides, and the distance between the blank area and the two light incident sides is unequal, and the distance between the area with the highest microstructure distribution density in the low-density area and the two light incident sides is equal.

[0011] Another technical means of the present invention is that the back plate has a bottom plate portion and an enclosing portion provided on the periphery of the bottom plate portion, and the sleeve is provided on the bottom plate portion and extends in one direction away from the bottom plate portion.

[0012] Another technical means of the present invention is that the back plate has a bottom plate portion and an enclosing portion provided on the periphery of the bottom plate portion, and the sleeve is provided on the bottom plate portion and extends in both directions away from the bottom plate portion.

[0013] Another technical means of the present invention is that the light absorption rate of the sleeve is greater than that of the back plate.

[0014] Another technical means of the present invention is characterized in that the sleeve is formed with an internal thread.

[0015] Another technical solution of the present invention is that the backlight module further includes a light blocking member annularly mounted on the outer periphery of the sleeve.

[0016] Another technical means of the present invention is that the backlight module further includes a light-shielding member annularly mounted on the sleeve, and the light-shielding member has an annular body portion fitted into the sleeve, a top edge portion extending radially inward of the annular body portion and abutting against the top edge of the sleeve, and a pressing portion extending radially outward of the annular body portion, and the annular body portion abuts against the outer peripheral surface of the sleeve.

[0017] Another technical means of the present invention is that the backlight module further includes a light-shielding member annularly mounted on the sleeve, the light-shielding member having an annular body portion fitted into the sleeve, a top edge portion extending radially outward from the annular body portion, and a pressing portion extending from the top edge portion, the annular body portion being attached to the inner surface of the sleeve, and the edge of the sleeve being covered by the annular body portion, the top edge portion and the pressing portion.

[0018] Another technical solution of the present invention is that the backlight module further includes at least one optical film, which has a through hole that is fitted into the sleeve, and the optical film is disposed between the light guide plate and the light blocking member.

[0019] Another object of the present invention is to provide a display device including the backlight module and a display panel mounted on the backlight module.

[0020] Another object of the present invention is to provide a display device including the backlight module and a display panel mounted on the backlight module, the display panel being in contact with the light blocking member.

[0021] The advantage of the side-entry backlight module with light leakage prevention function of this invention is that by designing the distribution density of the microstructures in the high-density region to be greater than the average distribution density of the microstructures in the low-density region, the probability of the light rays being reflected and emitted after passing through the high-density region is increased, thereby improving brightness, overcoming the problem of dark shadows caused by the installation of the sleeve, and utilizing the tendency change of the microstructures in the high-density and low-density regions to improve the light emission uniformity and optical quality of the entire light-emitting surface. [Brief explanation of the drawings]

[0022] The above and other objects, features, and advantages of the present invention will become apparent from the following description of the preferred embodiments with reference to the accompanying drawings. [Figure 1] 1 is an exploded perspective view of a preferred embodiment of a backlight module according to the present invention; [Figure 2] 3 is a schematic diagram illustrating the distribution of microstructures on the reflective surface of the light guide plate when the backlight module of the present invention is light-incident from one side; [Figure 3] 3 is a schematic diagram illustrating the distribution of microstructures on the reflective surface of the light guide plate when the backlight module of the present invention is configured with two-sided light input. [Figure 4]FIG. 4 is a partially enlarged cross-sectional view illustrating the structure of the sleeve. [Figure 5] FIG. 10 is a partially enlarged cross-sectional view illustrating another embodiment of the sleeve. [Figure 6] 1 is a cross-sectional view of a preferred embodiment of a display device according to the present invention; [Figure 7] FIG. 10 is a partially enlarged cross-sectional view illustrating a second embodiment of the light blocking member. [Figure 8] FIG. 10 is a partially enlarged cross-sectional view illustrating a third embodiment of the light blocking member. DETAILED DESCRIPTION OF THE INVENTION

[0023] The scope of the utility model registration claims and technical contents related to the present invention will become clear from the following detailed description of preferred embodiments with reference to the accompanying drawings. Before the detailed description, please note that similar elements are designated by the same numbers. The directional terms referred to in the following embodiments, such as upper, lower, left, right, front, rear, bottom, top, etc., are merely directions referring to the accompanying drawings. Therefore, the directional terms used are for explanation purposes only and do not limit the present invention.

[0024] In the following description, the terms "about," "substantially," "nearly," or "the same" generally indicate a range of within 10%, 5%, 3%, 2%, 1%, or 0.5% of a given value. Here, a given number is an approximate number, i.e., unless specifically stated as "about," "substantially," "nearly," or "the same," the meaning of "about," "substantially," "nearly," or "the same" may be included.

[0025] 1 shows a preferred embodiment of a backlight module 2 of the present invention, which includes a backplate 21, a light guide plate 22 mounted on the backplate 21 and having at least one light incident edge 221, at least one light source 23 mounted on the light incident edge 221, and a sleeve 24 mounted on the backplate 21. The sleeve 24 passes through the light guide plate 22 in its axial direction. Referring to FIG. 2, a single-side light incident backlight module 2 of the present invention will be described, in which the number of light sources 23 is one. The light guide plate 22 has a plurality of microstructures 222. The light guide plate 22 has a blank area D0 where the sleeve 24 is formed and a first area D10 surrounding the blank area D0, with no microstructures 222 within the blank area D0. The first region D10 has at least one high-density region D11 and one low-density region D12, and the blank region D0 is located between the at least one high-density region D11 and the light incident side 221. The distribution density of the microstructures 222 in the high-density region D11 is greater than the average distribution density of the microstructures 222 in the low-density region D12, and the distribution density of the microstructures 222 in the low-density region D12 gradually increases in the direction away from the at least one light incident side 221, while the distribution density of the microstructures 222 in the high-density region D11 gradually decreases in the direction away from the at least one light incident side 221. The microstructures 222 in the light guide plate 22 destroy the total internal reflection of the light and guide the light upward, causing the light to exit toward the light output surface of the light guide plate 22. More specifically, when light source 23 projects light from light incident edge 221 and travels toward sleeve 24, and the light hits sleeve 24 and is blocked, a shadow area is created on the back side of sleeve 24 facing light incident edge 221 of light guide plate 22, resulting in a problem of insufficient brightness on the back side of sleeve 24. In this embodiment, when a ray of light passes through the shadow area, the highly densely distributed microstructures 222 in high-density region D11 can increase the probability of the ray of light being reflected and emitted, which further improves the uniformity of the overall emitted light.By designing the distribution density of the microstructures 222 in the high-density region D11 to gradually decrease in the direction away from at least one light incident edge 221, and the distribution density of the microstructures 222 in the high-density region D11 to be greater than the average distribution density of the microstructures 222 in the low-density region D12, the probability that the light will be reflected and emitted after passing through the high-density region D11 can be increased, thereby improving the light output, overcoming the problem of dark shading caused by the installation of the sleeve 24, and utilizing the change in the distribution trend of the microstructures in the high-density region D11 and the low-density region D12 to improve the light output uniformity from the light incident edge 221 of the light guide plate 222 toward the sleeve 24, and further improving the light output uniformity and optical quality of the entire light-emitting surface.

[0026] In this embodiment, the backlight module 22 is applied to a driver monitoring system (DMS) of a vehicle, and is therefore typically mounted on a dashboard, with the sleeve 24 used to mount a photographic lens. To prevent the photographic lens from being blocked or interfered with by the steering wheel, the position of the sleeve 24 is shifted upward rather than in the center of the overall structure. Naturally, the position of the sleeve 24 may vary depending on the actual usage environment and is not limited to that disclosed in this embodiment. The detailed configuration of this embodiment will be described below.

[0027] 3, the light guide plate 22 has two light input edges 221, and two light sources 23 are provided corresponding to the two light input edges 221. Therefore, the first region D10 of the light guide plate 22 forms two high-density regions D11 corresponding to the two light sources 23, each corresponding to a farther light input edge 221, and a blank region D0 is located between each high-density region D11 and the corresponding light input edge 221. More specifically, the high-density region D11a corresponds to the farther light input edge 221a, and a low-density region D12a is provided corresponding to the high-density region D11a, and the high-density region D11a and the low-density region D12a are located on both sides of the blank region D0. The high-density region D11b corresponds to the relatively distant light incident side 221b, and a low-density region D12b is provided corresponding to the high-density region D11b, with the high-density region D11b and low-density region D12b located on opposite sides of the blank region D0. The two high-density regions D11a and D11b are located in the extension direction D of the line connecting the two light incident sides 221 and the blank region D0. The distribution density of the microstructures 222 in the high-density region D11 is greater than the average distribution density of the microstructures 222 in the low-density region D12. The distribution density of the microstructures 222 in the low-density region D12 gradually increases in the direction away from the corresponding light incident side 221, and the distribution density of the microstructures 222 in the high-density region D11 gradually decreases in the direction away from the corresponding light incident side 221. More specifically, the distribution density of the microstructures 222 in the low-density region D12a gradually increases in the direction away from the light incident side 221a, while the distribution density of the microstructures 222 in the high-density region D11a gradually decreases in the direction away from the light incident side 221a. The distribution density of the microstructures 222 in the low-density region D12b gradually increases in the direction away from the light incident side 221b, while the distribution density of the microstructures 222 in the high-density region D11b gradually decreases in the direction away from the light incident side 221b. The high-density region D11 is designed as a substantially fan-shaped region, with the blank region D0 as the center of the fan, and the distribution density of the microstructures 222 gradually decreases in the direction away from the blank region D0. In this way, the uniformity of the light output in the surrounding area adjacent to the blank region D0 of the first region D10 (i.e., the attachment position of the sleeve 24) can be finely adjusted.

[0028] In particular, to avoid bright lines around the blank area D0 of the light guide plate 22 where the sleeve 24 is located, the sleeve 24 is selected to have a higher light absorption rate than the backplate 21 so that the light can be absorbed by the light-absorbing effect of its outer surface. In this embodiment, the light guide plate 22 has through-holes for the sleeve 24 to pass through, and these through-holes are located in the blank area D0. However, light traveling through the light guide plate 22 may experience light leakage after passing through the through-holes. In conventional side-entry backlight modules, if the sleeve 24 has a metallic or white surface, this problem of light leakage through the through-holes is exacerbated. Therefore, the sleeve 24 in this embodiment is preferably black. In this way, the outer light-absorbing properties of the sleeve 24 are utilized to prevent the sleeve 24 from reflecting light back into the light guide plate 22, thereby improving optical quality.

[0029] 3, depending on the mounting position of the sleeve, the blank area D0 is located between the two light incident sides 221, and the distance between the blank area D0 and the two light incident sides 221 is not equal, but the area in the low-density area D12 where the microstructure distribution density is highest is equal to the distance between the two light incident sides 221. Of course, in actual implementation, depending on the mounting position of the sleeve, the distance between the blank area D0 and the two light incident sides 221 may be equal, and the distance between the area in the low-density area D12 where the microstructure distribution density is highest and the distance between the two light incident sides 221 may be equal.

[0030] Here, the microstructures 222 are disposed on the reflective surface 220 of the light guide plate 22. As shown in FIG. 1, the reflective surface 220 faces the back plate 21. To illustrate the distribution of the microstructures 222, in FIGS. 2 and 3, the light guide plate 22 appears at an angle with the reflective surface 220 facing upward. As shown in FIG. 1, the back plate 21 includes a base plate portion 211 and an enclosing portion 212 disposed around the periphery of the base plate portion 211. The sleeve 24 is disposed on the base plate portion 211. As shown in FIG. 4, the sleeve 24 extends in both directions away from the base plate portion 211. The sleeve 24 may be punched directly from the base plate portion 211, or may be formed and then crimped to the base plate portion 211. In another embodiment, as shown in FIG. 5, the sleeve 24 extends in one direction away from the base plate portion 211. In actual implementation, the shape of the sleeve 24 can be selected depending on the type of photographic lens or the installation environment of the backlight module 22. The bidirectionally extending sleeve 24 has one side as a member for fixing the light guide plate 22 and other optical elements, providing more stable structural support and facilitating assembly, while the other side can be used to fix other components such as a sensing module or a photographic lens. Furthermore, as shown in Fig. 4, the sleeve 24 may be formed with a female screw (or an attachment coupled with the female screw), and the photographic lens 90 may be connected to the sleeve 24 by threading. As shown in Fig. 5, the photographic lens 90 (not shown) may be placed in the sleeve 24 and then fixed in the sleeve 24 by another sealing member 91, which has the effect of simplifying the assembly process.

[0031] Referring to FIG. 1 , the backlight module 2 further includes a light blocking member 25 and a plurality of optical films 26 disposed in a sleeve 24. The sleeve 24 can be a member for fixing the light guide plate 22 and other optical films 26. The optical films 26 are disposed between the light guide plate 22 and the light blocking member 25, and each optical film 26 has a through-hole 261 corresponding to the sleeve 24. As shown in FIG. 4 , the light blocking member 25 has an annular body portion 251 fitted into the sleeve 24, a top edge portion 252 extending radially inward from the annular body portion 251 and abutting against the top edge of the sleeve 24, and a pressing portion 253 extending from the top edge portion 252. The annular body portion 251 is pressed against the outer circumferential surface of the sleeve 24. The installation of the light-blocking member 25 not only restricts the optical film 26 and the light guide plate 22, but also seals the gaps between the light-blocking sleeve 24 and the light guide plate 22 and the optical film 26, thereby avoiding the problem of light from the light-emitting member 222 leaking through the gaps and causing light leakage.

[0032] As shown in FIG. 3 , after light from the light source 23 enters the light guide plate 22, the microstructures 222 located on the reflective surface 220 of the light guide plate 22 disrupt the total internal reflection of the light and guide the light upward, guiding it toward the light output surface of the light guide plate 22. The sleeve 24 blocks the light, creating a shadow on the side of the sleeve 24 facing away from the light source 23. The distribution density of the microstructures 222 on the light guide plate 22 varies depending on the shadowed area. The high-density region D11 corresponds to the shadowed area, and the distribution density of the microstructures 222 there is greater than the average distribution density of the microstructures 222 in the low-density region D12. Therefore, the light quantity and brightness are improved after the light passes through the high-density region D11, thereby overcoming the shadow caused by the sleeve 24. The overall density distribution of the microstructures 222 also varies depending on the distance from the light source 23. As can be seen from Figure 3, the density distribution of the microstructures 222 is sparse near the light source 23 and becomes denser in the direction away from the light source 23, that is, the density of the microstructures 222 is densest at the central position where the amount of received light is the smallest. The high-density microstructures 222 improve the amount of light emitted at the central position, and further improve the light emission uniformity and optical quality of the entire light-emitting surface.

[0033] 3, the provision of the light blocking member 25 can prevent light from the light emitting member 222 from leaking through the gap between the optical film 26 and the sleeve 24 or between the light guide plate 22 and the sleeve 24. At the same time, the pressing portion 253 of the light blocking member 25 can position and press the optical film 26 and the light guide plate 22, preventing displacement of the optical film 26 or the light guide plate 22 and improving the stability of the overall structure after assembly. In this embodiment, the light blocking member 25 is made of an elastic material (e.g., rubber) and can be directly fitted into and fastened to the sleeve 24, making assembly convenient.

[0034] 6, a display panel 3 is provided on a backlight module 2, i.e., the display device of the present invention. In addition to being supported by a frame 27, the display panel 3 may also be placed on a light-blocking member 25, which prevents the display panel 3 from directly colliding with the sleeve 24 and thus protects the display panel 3.

[0035] In some embodiments, the light blocking member 25 may have a slightly different configuration. As shown in FIG. 7 , the light blocking member 25 may have an annular body 251 fitted into the sleeve 24, a top edge 252 extending radially outward from the annular body 251, and a pressing portion 253 extending from the top edge 252. The annular body 251 is attached to the inner surface of the sleeve 24. The edge of the sleeve 24 is collectively covered by the annular body 251, the top edge 252, and the pressing portion 253. Alternatively, as shown in FIG. 8 , the light blocking member 25 may have a single ring structure and be fixed to the top edge of the sleeve 24 with tape. The annular body 251 attached to the inner surface of the sleeve 24 may protect the photographing lens 90 or other sensing module provided in the sleeve 24 of the backlight module 2 from directly colliding with the sleeve 24.

[0036] In this invention, the distribution density of the microstructures 222 in the high-density region D11 of the light guide plate 22 is greater than that in the low-density region D12, thereby increasing the probability that light will be reflected and emitted after passing through the high-density region D11, thereby improving the light output and overcoming the problem of shadows caused by the sleeve 24. Furthermore, the change in the distribution trend of the microstructures 22 in the low-density region D12 is utilized to improve the overall light output uniformity from the light incident edge 221 of the light guide plate 22 toward the sleeve 24, as well as the light output uniformity adjacent to the sleeve 24, thereby achieving the effect of improving the optical quality of the light output surface of the backlight module 2. In addition, the light-blocking member 25 on the sleeve 24 prevents light leakage and improves the light output uniformity and rotation uniformity of the entire light-emitting surface of the backlight module 22, further improving the quality of the light-emitting surface, and effectively reducing the design value of the black matrix of the display panel 3. Furthermore, the light blocking member 25 is made of an elastic material and can be assembled by direct pressing, which reduces the assembly cost, reduces the number of assembly steps, reduces the mold opening cost, and reduces the manufacturing cost.

[0037] The above is merely a preferred embodiment of the present invention and does not limit the scope of the present invention. In other words, simple equivalent changes and modifications made based on the scope of the utility model claims and the description of the present invention are all within the scope of the present invention. [Explanation of symbols]

[0038] 2 Backlight Module 21 Backplate 211 Bottom plate part 212 Surrounding area 22 Light guide plate 220 Reflective surface 221 Light Side 221a Light entrance side 221b Light entrance side 222 Microstructure D0 Blank area D10 1st area D11 High density area D11a High density area D11b High density area D12 Low density area D12a low density area D12b Low density region 23 Light source 24 sleeve 25 Light blocking material 251 Annular body 252 Top edge 253 Pressing part 26 Optical Film 261 Through hole 27 frames 3 Display panel D Extension direction

Claims

1. A side-entry type backlight module with a light leakage prevention function, The back plate and a light guide plate provided on the back plate and having at least one light incident side; At least one light source provided on the at least one light entrance side; a sleeve provided on the back plate and penetrating the light guide plate along the axial direction of the sleeve; wherein the light guide plate has a plurality of microstructures, the light guide plate has a blank area where the sleeve is drilled and a first area surrounding the blank area, the blank area does not have the microstructures, the first area has at least one high-density area and a low-density area, the blank area is located between the at least one high-density area and the light incident side, the distribution density of the microstructures in the high-density area is greater than the average distribution density of the microstructures in the low-density area, the distribution density of the microstructures in the low-density area gradually increases in a direction away from the at least one light incident side, and the distribution density of the microstructures in the high-density area gradually decreases in a direction away from the at least one light incident side. A side-entry type backlight module with a light leakage prevention function.

2. The side-entry type backlight module with light leakage prevention function according to claim 1 , wherein the at least one high-density area is located in an extension direction of a line connecting the at least one light-entering side and the blank area.

3. 2. The side-entry type backlight module with light leakage prevention function described in claim 1, wherein the light guide plate has two light incident sides, the first region has two high-density regions, each high-density region corresponds to the light incident side that is far away, and the blank region is located between each high-density region and the corresponding light incident side.

4. A side-entry backlight module with light leakage prevention function as described in claim 3, wherein the blank area is located between the two light incident sides, and the distance between the blank area and the two light incident sides is equal, and the distance between the area with the highest distribution density of the microstructures in the low-density area and the two light incident sides is equal.

5. 4. A side-entry backlight module with light leakage prevention function as described in claim 3, wherein the blank area is located between the two light incident sides, and the distance between the blank area and the two light incident sides is not equal, and the distance between the area with the highest distribution density of the microstructures in the low-density area and the two light incident sides is equal.

6. 2. A side-entry type backlight module with a light leakage prevention function as described in claim 1, wherein the backplate comprises a bottom plate portion and an enclosing portion provided on the periphery of the bottom plate portion, and the sleeve is provided on the bottom plate portion and extends in a direction away from the bottom plate portion.

7. The side-entry type backlight module with a light leakage prevention function according to claim 1 , wherein the light absorption rate of the sleeve is greater than the light absorption rate of the backplate.

8. The side-entry type backlight module with a light leakage prevention function according to claim 1 , further comprising a light-blocking member annularly mounted on the outer circumferential surface of the sleeve.

9. 9. The side-entry type backlight module with light leakage prevention function described in claim 8, further comprising at least one optical film, the at least one optical film having a through hole fitted to correspond to the sleeve, and the at least one optical film being disposed between the light guide plate and the light-blocking member.

10. A display device comprising: a side-entry type backlight module with a light leakage prevention function according to any one of claims 1 to 9; and a display panel provided in the side-entry type backlight module with a light leakage prevention function.

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